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Sample records for title compounds mn12o8cl4o2cph8hmp6

  1. Incorporation of μ3-CO3 into an MnIII/MnIV Mn12 cluster: {[(cyclam)MnIV(μ-O)2MnIII(H2O)(μ-OH)]6(μ3-CO3)2}Cl8·24H2O

    Science.gov (United States)

    Levaton, Ben B.; Olmstead, Marilyn M.

    2010-01-01

    The centrosymmetric title cluster, hexa­aquadi-μ3-carbonato-hexa­cyclamhexa-μ2-hydroxido-dodeca-μ2-oxido-hexa­mang­an­ese(IV)hexa­manganese(III) octa­chloride tetra­cosa­hydrate, [Mn12(CO3)2O12(OH)6(C10H24N4)6(H2O)6]Cl8·24H2O, has two μ3-CO3 groups that not only bridge octahedrally coordinated MnIII ions but also act as acceptors to two different kinds of hydrogen bonds. The carbonate anion is planar within experimental error and has an average C—O distance of 1.294 (4) Å. The crystal packing is stabilized by O—H⋯Cl, O—H⋯O, N—H⋯Cl and N—H⋯O hydrogen bonds. Two of the four independent chloride ions are disordered over five positions, and eight of the 12 independent water mol­ecules are disordered over 21 positions. PMID:21587382

  2. Magnetic measurements and neutron diffraction study of the layered hybrid compounds Mn(C8H4O4)(H2O)2 and Mn2(OH)2(C8H4O4)

    International Nuclear Information System (INIS)

    Sibille, Romain; Mesbah, Adel; Mazet, Thomas; Malaman, Bernard; Capelli, Silvia; François, Michel

    2012-01-01

    Mn(C 8 H 4 O 4 )(H 2 O) 2 and Mn 2 (OH) 2 (C 8 H 4 O 4 ) layered organic–inorganic compounds based on manganese(II) and terephthalate molecules (C 8 H 4 O 4 2− ) have been studied by DC and AC magnetic measurements and powder neutron diffraction. The dihydrated compound behaves as a 3D antiferromagnet below 6.5 K. The temperature dependence of its χT product is typical of a 2D Heisenberg system and allows determining the in-plane exchange constant J≈−7.4 K through the carboxylate bridges. The magnetic structure confirms the in-plane nearest neighbor antiferromagnetic interactions and the 3D ordering. The hydroxide based compound also orders as a 3D antiferromagnet with a higher Néel temperature (38.5 K). Its magnetic structure is described from two antiferromagnetically coupled ferromagnetic sublattices, in relation with the two independent metallic sites. The isothermal magnetization data at 2 K are consistent with the antiferromagnetic ground-state of these compounds. However, in both cases, a slope change points to field-induced modification of the magnetic structure. - Graphical abstract: The macroscopic magnetic properties and magnetic structures of two metal-organic frameworks based on manganese (II) and terephthalate molecules are presented. Highlights: ► Magnetic study of Mn(C 8 H 4 O 4 )(H 2 O) 2 and Mn 2 (OH) 2 (C 8 H 4 O 4 ). ► Two compounds with common features (interlayer linker/distance, S=5/2 spin). ► Magnetic measurements quantitatively analyzed to deduce exchange constants. ► Magnetic structures determined from neutron powder diffraction experiments.

  3. Hydrostatic Compression of 2,4,6,8,10,12 hexanitrohexaaza isowurtzitane (CL20) Co Crystals

    Science.gov (United States)

    2016-12-01

    ARL-TR-7901 ● DEC 2016 US Army Research Laboratory Hydrostatic Compression of 2,4,6,8,10,12- hexanitrohexaaza-isowurtzitane (CL20... Hydrostatic Compression of 2,4,6,8,10,12- hexanitrohexaaza-isowurtzitane (CL20) Co-Crystals by DeCarlos Taylor Weapons and Materials...Technical Report 3. DATES COVERED (From - To) October 2015–September 2016 4. TITLE AND SUBTITLE Hydrostatic Compression of 2,4,6,8,10,12

  4. Unprecedented connection mode of [V{sub 16}Sb{sub 4}O{sub 42}(H{sub 2}O)]{sup 8-} cluster anions by Mn{sup 2+} centered complexes. Solvothermal synthesis and properties of {[Mn(teta)]_4V_1_6Sb_4O_4_2(H_2O)}{sub n}.[(H{sub 2}O){sub 12}]{sub n}

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Maren; Naether, Christian; Bensch, Wolfgang [Institute of Inorganic Chemistry, Christian-Albrechts-University of Kiel (Germany); Leusen, Jan van; Koegerler, Paul [Institute of Inorganic Chemistry, RWTH Aachen University, Aachen (Germany)

    2017-11-17

    The new compound {[Mn(teta)]_4V_1_6Sb_4O_4_2}{sub n}.[(H{sub 2}O){sub 12}]{sub n} (teta = triethylenetetraamine) was synthesized under solvothermal conditions. The crystal structure features the high nuclearity [V{sub 16}{sup IV}Sb{sub 4}{sup III}O{sub 42}(H{sub 2}O)]{sup 8-} cluster anion, which consists of two rings composed of 8 edge-sharing VO{sub 5} polyhedra. The rings are perpendicular to each other generating four niches, which are occupied by two VO{sub 5} pyramids and two handle-like Sb{sub 2}O{sub 5} units. The two unique anions are each surrounded by eight Mn{sup 2+} centered complexes via Mn-O{sub term}-V bonds. Such an expansion has never been observed in heterometal polyoxovanadate chemistry. The connection mode between cluster anions and complex cations generates two individual layers stacked onto each other. Between the layers weak Sb..O contacts are observed. The crystal water molecules are mainly located in the empty space between the layers. Upon heating H{sub 2}O molecules are removed, while the crystal structure remains intact. The magnetic behavior is dominated by strong antiferromagnetic exchange interactions between the central V{sup 4+} ions, while the interaction between the cluster anion and central Mn{sup 2+} ions is significantly less pronounced. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Improved Charge Transfer in a Mn2O3@Co1.2Ni1.8O4 Hybrid for Highly Stable Alkaline Direct Methanol Fuel Cells with Good Methanol Tolerance.

    Science.gov (United States)

    Liu, Yan; Chen, Yuanzhen; Li, Sai; Shu, Chenyong; Fang, Yuan; Song, Bo

    2018-03-21

    A three-dimensional Mn 2 O 3 @Co 1.2 Ni 1.8 O 4 hybrid was synthesized via facile two-step processes and employed as a cathode catalyst in direct methanol fuel cells (DMFCs) for the first time. Because of the unique architecture with ultrathin and porous nanosheets of the Co 1.2 Ni 1.8 O 4 shell, this composite exhibits better electrochemical performance than the pristine Mn 2 O 3 . Remarkably, it shows excellent methanol tolerance, even in a high concentration solution. The DMFC was assembled with Mn 2 O 3 @Co 1.2 Ni 1.8 O 4 , polymer fiber membranes, and PtRu/C as the cathode, membrane, and anode, respectively. The power densities of 57.5 and 70.5 mW cm -2 were recorded at 18 and 28 °C, respectively, especially the former is the best result reported in the literature at such a low temperature. The stability of the Mn 2 O 3 @Co 1.2 Ni 1.8 O 4 catalyzed cathode was evaluated, and the results show that this compound possesses excellent stability in a high methanol concentration. The improved electrochemical activity could be attributed to the narrow band gap of the hybrid, which accelerates the electrons jumping from the valence band to the conduction band. Therefore, Mn III could be oxidized into Mn IV more easily, simultaneously providing an electron to the absorbed oxygen.

  6. Structuring effects of [Ln6O(OH)8(NO3)6(H2O)12]2+ entities

    International Nuclear Information System (INIS)

    Guillou, O.; Daiguebonne, C.; Calvez, G.; Le Dret, F.; Car, P.-E.

    2008-01-01

    In order to obtain highly porous lanthanide-based coordination polymers we are currently investigating reactions between [Ln 6 O(OH) 8 (NO 3 ) 6 (H 2 O) 12 ] 2+ di-cationic hexanuclear entities and sodium salts of benzene-poly-carboxylic acids. Two new coordination polymers obtained during this study are reported here. In both cases, the hexanuclear entity has been destroyed during the reaction. However the resulting compounds are original thanks to a structuring effect of the poly-metallic complex. The first compound of chemical formula [Y 2 (C 8 H 4 O 4 ) 3 (DMF)(H 2 O)],2DMF crystallizes in the monoclinic system, space group P121/n (n o 14) with a = 16.0975(3) A, b = 14.4605(3) A, c = 17.7197(4) A, β = 92.8504(9) o and Z = 4. The second compound of chemical formula Y 2 (NO 3 ) 2 (C 10 H 2 O 8 )(DMF) 4 crystallizes in the triclinic system, space group P-1 (n o 2) with a = 7.5312(3) A, b = 9.0288(3) A, c = 13.1144(6) A, α = 92.6008(14) o , β = 94.9180(14) o , γ = 112.1824(16) o and Z = 2. Both crystal structures are 2D. Both crystal structures are described and the original structural features are highlighted and related to a potential structuring effect of the hexanuclear precursor

  7. Diaqua{6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne]diphenolato-κ2O,N,N′,O′}manganese(III perchlorate 18-crown-6 hemisolvate monohydrate

    Directory of Open Access Journals (Sweden)

    Ming-Ming Yu

    2009-02-01

    Full Text Available In the cation of the title compound, [Mn(C18H18N2O4(H2O2]ClO4·0.5C12H24O6·H2O, the MnIII ion is coordinated by two water O atoms, and two O atoms and two N atoms from the tetradentate 6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne]diphenolate ligand, completing a distorted octahedral geometry. One O atom of the 18-crown-6-ether is disordered over two positions with occupancies of 0.70 (2 and 0.30 (2.

  8. Siudaite, Na8(Mn2+ 2Na)Ca6Fe3+ 3Zr3NbSi25O74(OH)2Cl·5H2O: a new eudialyte-group mineral from the Khibiny alkaline massif, Kola Peninsula

    Science.gov (United States)

    Chukanov, Nikita V.; Rastsvetaeva, Ramiza K.; Kruszewski, Łukasz; Aksenov, Sergey M.; Rusakov, Vyacheslav S.; Britvin, Sergey N.; Vozchikova, Svetlana A.

    2018-03-01

    The new eudialyte-group mineral siudaite, ideally Na8(Mn2+ 2Na)Ca6Fe3+ 3Zr3NbSi25O74(OH)2Cl·5H2O, was discovered in a peralkaline pegmatite situated at the Eveslogchorr Mt., Khibiny alkaline massif, Kola Peninsula, Russia. The associated minerals are aegirine, albite, microcline, nepheline, astrophyllite, and loparite-(Ce). Siudaite forms yellow to brownish-yellow equant anhedral grains up to 1.5 cm across. Its lustre is vitreous, and the streak is white. Cleavage is none observed. The Mohs' hardness is 4½. Density measured by hydrostatic weighing is 2.96(1) g/cm3. Density calculated using the empirical formula is equal to 2.973 g/cm3. Siudaite is nonpleochroic, optically uniaxial, negative, with ω = 1.635(1) and ɛ = 1.626(1) (λ = 589 nm). The IR spectrum is given. The chemical composition of siudaite is (wt%; electron microprobe, H2O determined by HCN analysis): Na2O 8.40, K2O 0.62, CaO 9.81, La2O3 1.03, Ce2O3 1.62, Pr2O3 0.21, Nd2O3 0.29, MnO 6.45, Fe2O3 4.51. TiO2 0.54, ZrO2 11.67, HfO2 0.29, Nb2O5 2.76, SiO2 47.20, Cl 0.54, H2O 3.5, -O = Cl - 0.12, total 99.32. According to Mössbauer spectroscopy data, all iron is trivalent. The empirical formula (based on 24.5 Si atoms pfu, in accordance with structural data) is [Na7.57(H2O)1.43]Σ9(Mn1.11Na0.88Ce0.31La0.20Nd0.05Pr0.04K0.41)Σ3(H2O)1.8(Ca5.46Mn0.54)Σ6(Fe3+ 1.76Mn2+ 1.19)Σ2.95Nb0.65(Ti0.20Si0.50)Σ0.71(Zr2.95Hf0.04Ti0.01)Σ3Si24.00Cl0.47O70(OH)2Cl0.47·1.82H2O. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is trigonal, space group R3m, with a = 14.1885(26) Å, c = 29.831(7) Å, V = 5200.8(23) Å3 and Z = 3. Siudaite is chemically related to georgbarsanovite and is its analogue with Fe3+-dominant M2 site. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.38 (60) (-114), 4.29 (55) (-225), 3.389 (47) (131), 3.191 (63) (-228). 2.963 (100) (4-15), 2.843 (99) (-444), 2.577 (49) (3-39). Siudaite is named after the Polish

  9. NMRON on a mixed halide antiferromagnet, (54Mn)Mn(Cl0.6Br0.4)2.4H2O

    International Nuclear Information System (INIS)

    Chaplin, D.H.; Harker, S.J.; Hutchison, W.D.; Bowden, G.J.

    2000-01-01

    Full text: Recently we reported on the significant gains that can be made in Low Temperature Nuclear Orientation (LTNO) of the magnetically dominant species in an antiferromagnetic single crystal by heterogeneous mixing of the halide ligands. This new approach relies on enhanced nuclear spin lattice relaxation (NSLR) at the magnetic ion, in this case Mn, through broadbanded electronic magnons, in the cooled, single crystal host. Whereas the isomorphous terminal compounds ( 54 Mn)MnCI 2 .4H 2 O and ( 54 Mn)MnBr 2 .4H 2 O, have yielded zero field directional anisotropies of only 5% and 14%, respectively, from the daughter gamma from the long-lived parent 54 Mn, the mixed halides have yielded up to 40% zero field gamma anisotropy at the same base temperature of about 7-8 millikelvin. This improved zero field LTNO provides sufficient sensitivity to enable meaningful NMRON studies of the details of the hyperfine parameters at the Mn site in these mixed halide systems. In this paper we provide the NMRON results for single crystal ( 54 Mn)Mn(CI 0.6 Br 0.4 ) 2 .4H 2 O and compare them with the two terminal compounds which possess surprisingly different NMR responses due to different ratios of magnetic exchange to magnetic anisotropy fields. It is shown that whereas the static magnetic hyperfine field at the Mn nucleus is largely unchanged, and the spin flop field nicely interpolates when compared with the terminal compounds, there are significant differences in the pseudoquadrupolar splittings and sub-resonance linewidths

  10. Systematic study of spin crossover and structure in [Co(terpyRX)2](Y)2 systems (terpyRX = 4'-alkoxy-2,2':6',2''-terpyridine, X = 4, 8, 12, Y = BF4(-), ClO4(-), PF6(-), BPh4(-))

    DEFF Research Database (Denmark)

    Nielsen, Pia; Nielsen, Hans Toftlund; Bond, Andrew

    2009-01-01

    A family of spin crossover cobalt(II) complexes of the type [Co(terpyRX)(2)](Y)(2) x nH(2)O (X = 4, 8, 12 and Y = BF(4)(-), ClO(4)(-), PF(6)(-), BPh(4)(-)) has been synthesized, whereby the alkyl chain length, RX, and counteranion, Y, have been systematically varied. The structural (single crystal...

  11. Simple preparations of Pd6Cl12, Pt6Cl12, and Qn[Pt2Cl8+n], n=1, 2 (Q=TBA+, PPN+) and structural characterization of [TBA][Pt2Cl9] and [PPN]2[Pt2Cl10].C7H8.

    Science.gov (United States)

    Dell'Amico, Daniela Belli; Calderazzo, Fausto; Marchetti, Fabio; Ramello, Stefano; Samaritani, Simona

    2008-02-04

    The hexanuclear Pd6Cl12, i.e., the crystal phase classified as beta-PdCl2, was obtained by reacting [TBA]2[Pd2Cl6] with AlCl3 (or FeCl3) in CH2Cl2. The action of AlCl3 on PtCl42-, followed by digestion of the resulting solid in 1,2-C2H4Cl2 (DCE), CHCl3, or benzene, produced Pt6Cl12.DCE, Pt6Cl12.CHCl3, or Pt6Cl12.C6H6, respectively. Treating [TBA]2[PtCl6] with a slight excess of AlCl3 afforded [TBA][Pt2Cl9], whose anion was established crystallographically to be constituted by two "PtCl6" octahedra sharing a face. Dehydration of H2PtCl6.nH2O with SOCl2 gave an amorphous compound closely analyzing as PtCl4, reactive with [Q]Cl in SOCl2 to yield [Q][Pt2Cl9] or [Q]2[Pt2Cl10], depending on the [Q]Cl/Pt molar ratio (Q=TBA+, PPN+). A single-crystal X-ray diffraction study has shown [PPN]2[Pt2Cl10].C7H8 to contain dinuclear anions formed by two edge-sharing PtCl6 octahedra.

  12. Synthesis of LiMn2O4 and LiCr0.2Mn1.8O4 powders by modified Pechini process

    Directory of Open Access Journals (Sweden)

    Alexandre Urbano

    2009-03-01

    Full Text Available LiMn2O4 and LiCr0.2Mn1.8O4 powders were synthesized by Pechini process, modified in order to reduce the number of steps and to work at temperatures below or equal to 400oC. Both phases crystallize in the same spinel structure with lattice constants of 8.21 and 8.22 Å respectively. Although the annealing temperature was low, the cristallinity is good and no residual amounts of organic material were detected.

  13. Comment on 'Pressure-induced changes in transport properties of layered La1.2Ca1.8Mn2O7'

    International Nuclear Information System (INIS)

    Ganguly, R.; Siruguri, V.; Gopalakrishnan, I.K.; Yakhmi, J.V.

    2000-01-01

    We show that the compound La 1.2 Ca 1.8 Mn 2 O 7 does not form with layered Sr 3 Ti 2 O 7 -type structure as reported by Kamenev et al. [Phys. Rev. B 56, R12 688 (1997)]. Detailed analysis of the powder x-ray diffraction pattern of this compound (synthesized by using the solid-state method) by Rietveld method shows that it forms a multiphase mixture comprising hole-doped perovskite manganates (La 1-x Ca x MnO 3 ) as the majority phases and CaO as the minority phase

  14. Unveiling the Structural Evolution of Ag1.2Mn8O16 under Coulombically Controlled (De)Lithiation

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jianping [Department; Hu, Xiaobing [Energy; Brady, Alexander B. [Department; Wu, Lijun [Energy; Zhu, Yimei [Energy; Takeuchi, Esther S. [Department; Energy; Department; Marschilok, Amy C. [Department; Department; Takeuchi, Kenneth J. [Department; Department

    2018-01-02

    MnO2 materials are considered promising cathode materials for rechargeable lithium, sodium, and magnesium batteries due to their earth abundance and environmental friendliness. One polymorph of MnO2, α-MnO2, has 2 × 2 tunnels (4.6 Å × 4.6 Å) in its structural framework, which provide facile diffusion pathways for guest ions. In this work, a silver-ion-containing α-MnO2 (Ag1.2Mn8O16) is examined as a candidate cathode material for Li based batteries. Electrochemical stability of Ag1.2Mn8O16 is investigated through Coulombically controlled reduction under 2 or 4 molar electron equivalents (e.e.). Terminal discharge voltage remains almost constant under 2 e.e. of cycling, whereas it continuously decreases under repetitive reduction by 4 e.e. Thus, detailed structural analyses were utilized to investigate the structural evolution upon lithiation. Significant increases in lattice a (17.7%) and atomic distances (~4.8%) are observed when x in LixAg1.2Mn8O16 is >4. Ag metal forms at this level of lithiation concomitant with a large structural distortion to the Mn–O framework. In contrast, lattice a only expands by 2.2% and Mn–O/Mn-Mn distances show minor changes (~1.4%) at x < 2. The structural deformation (tunnel breakage) at x > 4 inhibits the recovery of the original structure, leading to poor cycle stability at high lithiation levels. This report establishes the correlation among local structure changes, amorphization processes, formation of Ag0, and long-term cycle stability for this silver-containing α-MnO2 type material at both low and high lithiation levels.

  15. NCI calculations for understanding a physical phase transition in (C6H14N2)[Mn(H2O)6](SeO4)2

    Science.gov (United States)

    Naïli, Houcine; François, Michel; Norquist, Alexander J.; Rekik, Walid

    2017-12-01

    An organically templated manganese selenate, (C6H14N2)[Mn(H2O)6](SeO4)2, has been synthesized by slow evaporation and crystallographically characterized. The title compound crystallizes at room temperature in the monoclinic centrosymmetric space group P21/n, with the following unit cell parameters: a = 7.2373(4) Å; b = 12.5600(7) Å; c = 10.1945(7) Å; β = 91.155(4)°, V = 926.50(10) Å3and Z = 2. Its crystal structure is built of manganese(II) cations coordinated by six water molecules in octahedral geometry, disordered dabcodiium cations and selenate anions, resulting in an extensive hydrogen-bonding network. Differential scanning calorimetry (DSC) measurement indicated that the precursor undergoes a reversible phase transition at about 216 and 218 K during the cooling and heating processes respectively. Below this temperature the title compound is noncentrosymmetric with space group P21 and lattice parameters a = 7.2033(8) Å; b = 12.4981(13) Å; c = 10.0888(11) Å; β = 91.281(2)°, V = 908.04(17) Å3 and Z = 2. The disorder-order transformation of the C atoms of (C6H14N2)2+ cation may drive the structural phase transition. The low temperature phase obtained by breaking symmetry presents a fully ordered structure. The noncovalent interaction (NCI) method was used not only to locate, quantify, and visualize intermolecular interactions in the high and low temperature phases but also to confirm the phase transition detected by DSC measurement. The thermal decomposition of this new compound proceeds through four stages giving rise to the manganese oxide as final product at 850 °C.

  16. Study of NaBH4 reaction with RhCl4H2O and H2PtCl6·6H2O in dimethylformamide

    International Nuclear Information System (INIS)

    Khain, V.S.; Val'kova, V.P.

    1988-01-01

    Data on study of NaBH 4 reactions with RhCl 3 x4H 2 O and H 2 PtCl 6 x6H 2 O in dimethylformamide, which is a good solvent of both complex hydride and compounds of platinum metals are presented. Rhodium (3) and platinum (4) reduction by sodium tetrahydridoborate in dimethylformamide proceeds quantitatively up to element state. Depositions of powder-like rhodium and platinum or their sols stable up to 8 months are formed depending on the ratio of concentrations of the reacting substances. Stoichiometry of redox-reactions is established based on spectrophotometric, gasovolumetric measurements,

  17. Structural and dielectric characteristics of double perovskite La2(NiFe)1/2MnO6

    Science.gov (United States)

    Nasir, Mohd.; Kandasami, Asokan; Sen, Somaditya

    2018-05-01

    Recently, La2NiMnO6 has drawn significant interest because large magnetic field induced changes in dielectric properties makes this compound a promising material for potential spintronic device applications. In the present study, the structural and dielectric characteristics of sol-gel prepared La2(Ni1/2Fe1/2)MnO6 double perovskite ceramics were evaluated. La2(Ni1/2Fe1/2)MnO6 was crystallized in the monoclinic P21/n structure with ordered Ni2+/Fe2+ and Mn4+ cations. A giant dielectric constant with relaxor-like behavior was observed, which was attributed to the dipolar effects arising from hopping between Ni2+/Fe2+ and Mn4+ ions.

  18. Site-specific ligation of anthracene-1,8-dicarboxylates to an Mn12 core: a route to the controlled functionalisation of single-molecule magnets.

    Science.gov (United States)

    Pacchioni, Mirko; Cornia, Andrea; Fabretti, Antonio C; Zobbi, Laura; Bonacchi, Daniele; Caneschi, Andrea; Chastanet, Guillaume; Gatteschi, Dante; Sessoli, Roberta

    2004-11-21

    A novel single-molecule magnet of the Mn12 family, [Mn12O12(O2CC6H5)8(L)4(H2O)4].8CH2Cl2, has been synthesised by site-specific ligand exchange using a tailor-made dicarboxylate (L2-), which leads to selective occupation of axial binding sites.

  19. Systems Tl2MoO4-E(MoO4)2, where E=Zr or Hf, and the crystal structure of Tl8Hf(MoO4)6

    International Nuclear Information System (INIS)

    Bazarov, B.G.; Bazarova, Ts.T.; Fedorov, K.N.; Bazarova, Zh.G.; Chimitova, O.D.; Klevtsova, R.F.; Glinskaya, L.A.

    2006-01-01

    Systems Tl 2 MoO 4 -E(MoO 4 ) 2 (E=Zr, Hf) were studied by X-ray diffraction, differential thermal analysis and IR spectroscopy. Formation of Tl 8 E(MoO 4 ) 6 and Tl 2 E(MoO 4 ) 2 compounds was established. Phase T-x diagrams of the Tl 2 MoO 4 -Zr(MoO 4 ) 2 system were constructed. Monocrystals were grown, and structure of Tl 8 Hf(MoO 4 ) 6 was studied. The compound is crystallized in monoclinic syngony with elementary cell parameters a=9.9688(6), b=18.830(1), c=7.8488(5) A, β=108.538(1) Deg, Z=2, sp. gr. C2/m. The isolated group [HfMo 6 O 24 ] 8- is responsible for fundamental fragment of the structure. Three varieties of crystallographically independent Tl-polyhedra fill space evenly between fragments [HfMo 6 O 24 ] 8- forming three-dimensional form [ru

  20. Phase transitions and molecular motions in [Ni(ND3)6](ClO4)2

    International Nuclear Information System (INIS)

    Migdal-Mikuli, Anna; Mikuli, Edward; Gorska, Natalia; Kowalska, Aneta; Ulanski, Jacek

    2004-01-01

    [Ni(ND 3 ) 6 ](ClO 4 ) 2 has three solid phases between 100 and 300 K. The phase transitions temperatures at heating (T C1 h =164.1 K and T C2 h =145.1 K) are shifted, as compared to the non-deuterated compound, towards the lower temperature of ca. 8 and 5 K, respectively. The ClO 4 - anions perform fast, picosecond, isotropic reorientation with the activation energy of 6.6 kJ mol -1 , which abruptly slow down at T C1 c phase transition, during sample cooling. The ND 3 ligands perform fast uniaxial reorientation around the Ni-N bond in all three detected phases, with the effective activation energy of 2.9 kJ mol -1 . The reorientational motion of ND 3 is only slightly distorted at the T C1 phase transition due to the dynamical orientational order-disorder process of anions. The low value of the activation energy for the ND 3 reorientation suggests that this reorientation undergoes the translation-rotation coupling, which makes the barrier to the rotation of the ammonia ligands not constant but fluctuating. The phase polymorphism and the dynamics of the molecular reorientations of the title compound are similar but not quite identical with these of the [Ni(NH 3 ) 6 ](ClO 4 ) 2

  1. Tris(dibenzoylmethanido-κ2O,O′[(6S,8S-(+-7,7-dimethyl-3-(2-pyridyl-5,6,7,8-tetrahydro-6,8-methanoisoquinoline-κ2N,N′]gadolinium(III

    Directory of Open Access Journals (Sweden)

    Xi-Li Li

    2009-09-01

    Full Text Available In the title compound, [Gd(C15H11O23(C17H18N2], the GdIII atom is coordinated by six O atoms from three β-diketonate ligands and two N atoms from a chiral ligand LS,S-(+-7,7-dimethyl-3-(2-pyridyl-5,6,7,8-tetrahydro-6,8-methanoisoquinoline, in a coordination geometry best described as distorted square-antiprismatic.

  2. Synthesis and Characterization of TiO2(B Nanotubes Prepared by Hydrothermal Method Using [Ti8O12(H2O24]Cl8.HCl.7H2O as Precursor

    Directory of Open Access Journals (Sweden)

    Hari Sutrisno

    2010-04-01

    Full Text Available Low-dimension TiO2-related material has been synthesized by hydrothermal treatment of [Ti8O12(H2O24]Cl8.HCl.7H2O crystal as precursor in a 10 M NaOh aqueous solution at 150 C for 24 h. Characterization of the obtained product was carried out by a range of techniques including X-ray diffraction (XRD, high resolution scanning electron microscopy (HRSEM, high resolution transmission electron microscopy (HRTEM, Raman spectroscopy and nitrogen adsorption-desorption isotherm (Brunauer-Emmett-Teller (BET-Barret-Joyner-Halender (BJH. From HRTEM, XRD and Raman spectra showed that the obtained product has a TiO2(B structure. According to HRTEM observations, it was found that TiO2(B has nanotubular structure with approximately 5-8 nm in outer and 3-6 nm in inner diameter. The BET surface area of TiO2(B nanotubes is quiet large, values of 418.3163 m2/g being obtained. Pore structure analyisis by the BJH method showed that the average pore diameter of TiO2(B nanotubes has 5.5781 nm.

  3. Synthesis and electrochemical properties of LiNi0.4Mn1.5Cr0.1O4 and Li4Ti5O12

    CSIR Research Space (South Africa)

    Liu, GQ

    2011-08-01

    Full Text Available Spinel compound LiNi0.4Mn1.5Cr0.1O4 (LNMCO) and Li4Ti5O12 (LTO) were synthesized by the sol-gel method and the solid-state method, respectively. The particle sizes of the products LiNi0.4Mn1.5Cr0.1O4 and Li4Ti5O12 were 0.5 to 2 um and 0.5 to 0.8 um...

  4. Aquachlorido{6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilodimethylidyne]diphenolato-κ2O1,N,N′,O1′}cobalt(III monohydrate

    Directory of Open Access Journals (Sweden)

    Jianxin Xing

    2009-04-01

    Full Text Available The title compound, [Co(C18H18N2O4Cl(H2O]·H2O, contains a distorted octahedral cobalt(III complex with a 6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilodimethylidyne]diphenolate ligand, a chloride and an aqua ligand, and also a disordered water solvent molecule (half-occupancy. The CoIII ion is coordinated in an N2O3Cl manner. Weak O—H...O hydrogen bonds may help to stabilize the crystal packing.

  5. Crystal structure and optical property of complex perovskite oxynitrides ALi0.2Nb0.8O2.8N0.2, ANa0.2Nb0.8O2.8N0.2, and AMg0.2Nb0.8O2.6N0.4 (A = Sr, Ba)

    Science.gov (United States)

    Moon, Keon Ho; Avdeev, Maxim; Kim, Young-Il

    2017-10-01

    Oxynitride type complex perovskites AM0.2Nb0.8O3-xNx (A = Sr, Ba; M = Li, Na, Mg) were newly synthesized by the solid state diffusion of Li+, Na+, or Mg2+ into the layered oxide, A5Nb4O15, with concurrent O/N substitution. Neutron and synchrotron X-ray Rietveld refinement showed that SrLi0.2Nb0.8O2.8N0.2, SrNa0.2Nb0.8O2.8N0.2, and SrMg0.2Nb0.8O2.6N0.4 had body-centered tetragonal symmetry (I4/mcm), while those with A = Ba had simple cubic symmetry (Pm 3 ̅ m). In the tetragonal Sr-compounds, the nitrogen atoms were localized on the c-axial 4a site. However, the octahedral cations, M/Nb (M = Li, Na, Mg) were distributed randomly in all six compounds. The lattice volume of AM0.2Nb0.8O3-xNx was dependent on various factors including the type of A and the electronegativity of M. Compared to the simple perovskites, ANbO2N (A = Sr, Ba), AM0.2Nb0.8O3-xNx had wider band gaps (1.76-2.15 eV for A = Sr and 1.65-2.10 eV for A = Ba), but significantly lower sub-gap absorption.

  6. Crystal structure and spectroscopic analysis of a new oxalate-bridged MnII compound: catena-poly[guanidinium [[aquachloridomanganese(II]-μ2-oxalato-κ4O1,O2:O1′,O2′] monohydrate

    Directory of Open Access Journals (Sweden)

    Hiba Sehimi

    2016-05-01

    Full Text Available As part of our studies on the synthesis and the characterization of oxalate-bridged compounds M–ox–M (ox = oxalate dianion and M = transition metal ion, we report the crystal structure of a new oxalate-bridged MnII phase, {(CH6N3[Mn(C2O4Cl(H2O]·H2O}n. In the compound, a succession of MnII ions (situated on inversion centers adopting a distorted octahedral coordination and bridged by oxalate ligands forms parallel zigzag chains running along the c axis. These chains are interconnected through O—H...O hydrogen-bonding interactions to form anionic layers parallel to (010. Individual layers are held together via strong hydrogen bonds involving the guanidinium cations (N—H...O and N—H...Cl and the disordered non-coordinating water molecule (O—H...O and O—H...Cl, as well as by guanidinium π–π stacking. The structural data were confirmed by IR and UV–Visible spectroscopic analysis.

  7. Bis(2,2′-bipyridine[1,9-bis(diphenylphosphanyl-1,2,3,4,6,7,8,9-octahydropyrimido[1,2-a]pyrimidin-5-ium]ruthenium(II hexafluoridophosphate dibromide dichloromethane disolvate monohydrate

    Directory of Open Access Journals (Sweden)

    Alain Igau

    2013-12-01

    Full Text Available In the cation of the title complex, [Ru(C31H32N3P2(C10H8N22](PF6(Br2·2CH2Cl2·H2O, the ruthenium ion is coordinated in a distorted octahedral geometry by two 2,2′-bipyridine (bpy ligands and a chelating cationic N-diphenylphosphino-1,3,4,6,7,8-hexahydro-2-pyrimido[1,2-a]pyrimidine [(PPh22-hpp] ligand. The tricationic charge of the complex is balanced by two bromide and one hexafluoridophosphate counter-anions. The compound crystallized with two molecules of dichloromethane (one of which is equally disordered about a Cl atom and a water molecule. In the crystal, one of the Br anions bridges two water molecules via O—H...Br hydrogen bonds, forming a centrosymmetric diamond-shaped R42(8 motif. The cation and anions and the solvent molecules are linked via C—H...F, C—H...Br, C—H...Cl and C—H...O hydrogen bonds, forming a three-dimensional network.

  8. Synthesis and Properties of Layered-Structured Mn5O8 Nanorods

    DEFF Research Database (Denmark)

    Gao, Tao; Norby, Poul; Krumeich, Frank

    2010-01-01

    Mn5O8 nanorods were prepared by a topotactic conversion of γ-MnOOH nanorod precursors in nitrogen at 400 °C. The as-prepared Mn5O8 nanorods crystallized in a monoclinic structure (space group C2/m) with unit cell dimensions a = 10.3784(2) Å, b = 5.7337(7) Å, c = 4.8668(6) Å, and β = 109.491(6)°, ...

  9. (μ-3-Acetyl-5-carboxylato-4-methylpyrazolido-1:2κ4N2,O3:N1,O5-μ-chlorido-tetrapyridine-1κ2N,2κ2N-chlorido-1κCl-dicopper(II propan-2-ol solvate

    Directory of Open Access Journals (Sweden)

    Sergey Malinkin

    2009-10-01

    Full Text Available The title compound, [Cu2(C7H6N2O3Cl2(C5H5N4]·C3H8O, is a binuclear pyrazolate complex, in which the two CuII atoms have different coordination numbers and are connected by a bridging Cl atom. One CuII atom has a distorted square-pyramidal coordination environment formed by two pyridine N atoms, one bridging Cl atom and an N,O-chelating pyrazolate ligand. The other CuII atom adopts an octahedral geometry defined by two pyridine N atoms at the axial positions, two Cl atoms and the coordinated pyrazolate ligand in the equatorial plane. An O—H...O hydrogen bond connects the complex molecules and propan-2-ol solvent molecules into pairs. These pairs form columns along the a axis.

  10. Aquachlorido{6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethanylylidene]diphenolato-κ2O1,N,N′,O1′}cobalt(III dimethylformamide monosolvate

    Directory of Open Access Journals (Sweden)

    Yun Wei

    2012-04-01

    Full Text Available In the title compound, [Co(C18H18N2O4Cl(H2O]·C3H7NO, the CoIII ion is six-coordinated by a tetradentate 6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethanylylidene]diphenolate ligand, with a chloride ion and an aqua ligand in the apical positions. The compound crystallized as a dimethylformamide (DMF monosolvate. In the crystal, complex molecules are linked via O—Hwater...O hydrogen bonds to form a dimer-like arrangement. These dimers are linked via a C—H...Cl interaction, and the DMF molecule is linked to the complex molecule by C—H...O interactions.

  11. (4bS,8aS-1-Isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octahydrophenanthren-2-yl acetate

    Directory of Open Access Journals (Sweden)

    Radouane Oubabi

    2014-03-01

    Full Text Available The hemisynthesis of the title compound, C22H32O2, was carried out through direct acetylation reaction of the naturally occurring diterpene totarol [systematic name: (4bS,8aS-4b,8,8-trimethyl-1-propan-2-yl-5,6,7,8a,9,10-hexahydrophenanthren-2-ol]. The molecule is built up from three fused six membered rings, one saturated and two unsaturated. The central unsaturated ring has a half-chair conformation, whereas the other unsaturated ring displays a chair conformation. The absolute configuration is deduced from the chemical pathway. The value of the Hooft parameter [−0.10 (6] allowed this absolute configuration to be confirmed.

  12. Crystal structures of ZnCl2·2.5H2O, ZnCl2·3H2O and ZnCl2·4.5H2O

    Directory of Open Access Journals (Sweden)

    Erik Hennings

    2014-12-01

    Full Text Available The formation of different complexes in aqueous solutions is an important step in understanding the behavior of zinc chloride in water. The structure of concentrated ZnCl2 solutions is governed by coordination competition of Cl− and H2O around Zn2+. According to the solid–liquid phase diagram, the title compounds were crystallized below room temperature. The structure of ZnCl2·2.5H2O contains Zn2+ both in a tetrahedral coordination with Cl− and in an octahedral environment defined by five water molecules and one Cl− shared with the [ZnCl4]2− unit. Thus, these two different types of Zn2+ cations form isolated units with composition [Zn2Cl4(H2O5] (pentaaqua-μ-chlorido-trichloridodizinc. The trihydrate {hexaaquazinc tetrachloridozinc, [Zn(H2O6][ZnCl4]}, consists of three different Zn2+ cations, one of which is tetrahedrally coordinated by four Cl− anions. The two other Zn2+ cations are each located on an inversion centre and are octahedrally surrounded by water molecules. The [ZnCl4] tetrahedra and [Zn(H2O6] octahedra are arranged in alternating rows parallel to [001]. The structure of the 4.5-hydrate {hexaaquazinc tetrachloridozinc trihydrate, [Zn(H2O6][ZnCl4]·3H2O}, consists of isolated octahedral [Zn(H2O6] and tetrahedral [ZnCl4] units, as well as additional lattice water molecules. O—H...O hydrogen bonds between the water molecules as donor and ZnCl4 tetrahedra and water molecules as acceptor groups leads to the formation of a three-dimensional network in each of the three structures.

  13. Preparation of Zr(Mo,W)2O8 with a larger negative thermal expansion by controlling the thermal decomposition of Zr(Mo,W)2(OH,Cl)22H2O.

    Science.gov (United States)

    Petrushina, Mariya Yu; Dedova, Elena S; Filatov, Eugeny Yu; Plyusnin, Pavel E; Korenev, Sergei V; Kulkov, Sergei N; Derevyannikova, Elizaveta A; Sharafutdinov, Marat R; Gubanov, Alexander I

    2018-03-28

    Solid solutions of Zr(Mo,W) 2 O 7 (OH,Cl) 22H 2 O with a preset ratio of components were prepared by a hydrothermal method. The chemical composition of the solutions was determined by energy dispersive X-ray spectroscopy (EDX). For all the samples of ZrMo x W 2-x O 7 (OH,Cl) 22H 2 O (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0), TGA and in situ powder X-ray diffraction (PXRD) studies (300-1100 K) were conducted. For each case, the boundaries of the transformations were determined: Zr(Mo,W) 2 O 7 (OH,Cl) 22H 2 O → orthorhombic-ZrMo x W 2-x O 8 (425-525 K), orthorhombic-ZrMo x W 2-x O 8  → cubic-ZrMo x W 2-x O 8 (700-850 K), cubic-ZrMo x W 2-x O 8  → trigonal-ZrMo x W 2-x O 8 (800-1050 K for x > 1) and cubic-ZrMo x W 2-x O 8  → oxides (1000-1075 K for x ≤ 1). The cell parameters of the disordered cubic-ZrMo x W 2-x O 8 (space group Pa-3) were measured within 300-900 K, and the thermal expansion coefficients were calculated: -3.5∙10 -6  - -4.5∙10 -6  K -1 . For the ordered ZrMo 1.8 W 0.2 O 8 (space group P2 1 3), a negative thermal expansion (NTE) coefficient -9.6∙10 -6  K -1 (300-400 K) was calculated. Orthorhombic-ZrW2O 8 is formed upon the decomposition of ZrW 2 O 7 (OH,Cl) 22H 2 O within 500-800 K.

  14. Reactions UF4 - ClO2F and UF5 - ClO2F

    International Nuclear Information System (INIS)

    Benoit, Raymond; Besnard, Ginette; Hartmanshenn, Olivier; Luce, Michel; Mougin, Jacques; Pelissie, Jean

    1970-02-01

    The study of the reaction UF 4 - ClO 2 F between 0 deg. and 100 deg. C, by various techniques (micro-sublimation, isopiestic method, IR and UV spectrography, thermogravimetry and X-ray diffraction) shows that intermediate steps are possible before the production of UF 5 . The whole reaction may be schematised by two equations: (1) n UF 4 + ClO 2 F → n UF x + ClO 2 (4 4 + ClO 2 F → UF x + 1/2 Cl 2 + O 2 . The more the temperature rises, the more the second equation becomes experimentally verified. The reaction at 0 deg. C between UF 5 and ClO 2 F may be represented by: UF 5 + ClO 2 F → UF 6 ClO 2 . The reactions: UF 5 + ClO 2 F → UF 6 + ClO 2 , UF 5 + ClO 2 F → UF 6 + 1/2 Cl 2 + O 2 are verified, the first and the second at 25 deg. C., the second from 50 deg. to 150 deg. C. From the results of AGRON it is possible to predict the residual solids before complete volatilization as UF 6 . The IR spectra of ClO 2 F adsorbed on UF 4 and UF x at 60 deg. C have been compared with those of gaseous ClO 2 F and UF 6 adsorbed on UF 4 . (authors) [fr

  15. 10,21-Dimethyl-2,7,13,18-tetraphenyl-3,6,14,17-tetraazatricyclo[17.3.1.18,12]tetracosa-1(23,2,6,8(24,9,11,13,17,19,21-decaene-23,24-diol cyclohexane 0.33-solvate

    Directory of Open Access Journals (Sweden)

    Sushil K. Gupta

    2011-10-01

    Full Text Available The title compound, C46H40N4O2·0.33C6H12, was obtained unintentionally as a product of an attempted synthesis of a cadmium(II complex of the [2,6-{PhSe(CH22N=CPh}2C6H2(4-Me(OH] ligand. The full tetraiminodiphenol macrocyclic ligand is generated by the application of an inversion centre. The macrocyclic ligand features strong intramolecular O—H...N hydrogen bonds. The dihedral angles formed between the phenyl ring incorporated within the macrocycle and the peripheral phenyl rings are 82.99 (8 and 88.20 (8°. The cyclohexane solvent molecule lies about a site of overline{3} symmetry. Other solvent within the lattice was disordered and was treated with the SQUEEZE routine [Spek (2009. Acta Cryst. D65, 148–155].

  16. Hydrothermal synthesis and crystal structure of a new molybdenum oxide compound with manganese-o-phen subunit: [Mn(o-phen)(H2O)MoO4]·H2O (o-phen=o-phenanthroline)

    International Nuclear Information System (INIS)

    Zhang Quanzheng; Lu Canzhong; Yang Wenbin; Chen Shumei; Yu Yaqin; He Xiang; Yan Ying; Liu Jiuhui; Xu Xinjiang; Xia Changkun; Wu Xiaoyuan; Chen Lijuan

    2004-01-01

    A new one-dimensional molybdenum oxide compound with manganese-o-phen subunit: [Mn(o-phen)(H 2 O)MoO 4 ]·H 2 O (1) (o-phen=o-phenanthroline) was synthesized by the hydrothermal reaction of Na 2 MoO 4 ·2H 2 O, MnSO 4 ·H 2 O, oxalic acid, o-phenanthroline (o-phen) and water. Its structure was determined by elemental analyses, ESR spectrum, TG analysis, IR spectrum and single-crystal X-ray diffraction. Compound 1 crystallizes in triclinic system, space group P-1 with a=7.0401(2) A, b=10.4498(2) A, c=10.5720(2) A, α=73.26(7) deg., β=83.34(8) deg., γ=77.33(9) deg., V=725.5089(0) A 3 , Z=2, and R 1 =0.0322 for 2337 observed reflections. Compound 1 exhibits one-dimensional chain structure. The chains are linked up via hydrogen bonding to 2D layers, which are further assembled through π-π stacking interactions to a 3D supermolecular structure

  17. Crystal structures and thermal decomposition of permanganates AE[MnO_4]_2 . n H_2O with the heavy alkaline earth elements (AE=Ca, Sr and Ba)

    International Nuclear Information System (INIS)

    Henning, Harald; Bauchert, Joerg M.; Conrad, Maurice; Schleid, Thomas

    2017-01-01

    Reexamination of the syntheses and crystal structures as well as studies of the thermal decomposition of the heavy alkaline earth metal permanganates Ca[MnO_4]_2 . 4 H_2O, Sr[MnO_4]_2 . 3 H_2O and Ba[MnO_4]_2 are the focus of this work. As an alternative to the very inelegant Muthmann method, established for the synthesis of Ba[MnO_4]_2 a long time ago, we employed a cation-exchange column loaded with Ba"2"+ cations and passed through an aqueous potassium-permanganate solution. We later used this alternative also with strontium- and calcium-loaded columns and all the compounds synthesized this way were indistinguishable from the products of the established methods. Ca[MnO_4]_2 . 4 H_2O exhibiting [CaO_8] polyhedra crystallizes in the orthorhombic space group Pccn with the lattice parameters a=1397.15(9), b=554.06(4) and c=1338.97(9) pm with Z=4, whereas Sr[MnO_4]_2 . 3 H_2O with [SrO_1_0] polyhedra adopts the cubic space group P2_13 with a=964.19(7) pm and Z=4. So the harder the AE"2"+ cation, the higher its demand for hydration in aqueous solution. Consequently, the crystal structure of Ba[MnO_4]_2 in the orthorhombic space group Fddd with a=742.36(5), b=1191.23(7) and c=1477.14(9) pm with Z=8 lacks any crystal water, but contains [BaO_1_2] polyhedra. During the thermal decomposition of Ca[MnO_4]_2 . 4 H_2O, the compound expels up to two water molecules of hydration, before the crystal structure collapses after the loss of the third H_2O molecule at 157 C. The crystal structure of Sr[MnO_4]_2 . 3 H_2O breaks down after the expulsion of the third water molecule as well, but this already occurs at 148 C. For both the calcium and the strontium permanganate samples, orthobixbyite-type α-Mn_2O_3 and the oxomanganates(III,IV) AEMn_3O_6 (AE=Ca and Sr) remain as final decomposition products at 800 C next to amorphous phases. On the other hand, the already anhydrous Ba[MnO_4]_2 thermally decomposes to hollandite-type BaMn_8O_1_6 and BaMnO_3 at 800 C.

  18. Neutron scattering studies on phase transitions in (CD3ND3)2CuCl4 and MnCl2.4H2O

    International Nuclear Information System (INIS)

    Steijger, J.J.M.

    1982-10-01

    In this thesis the results of neutron scattering experiments and measurements of the susceptibility on some compounds which display magnetic and/or structural phase transitions, are described. Following an introductory chapter, chapter 2 shows that neutron scattering can be used as a tool for unravelling problems in crystallographic and magnetic structure. The qualitative different scattering patterns for scatters are described. In chapters 3 and 4 an investigation on the layered ferromagnets (CH 3 NH 3 ) 2 CuCl 4 and (CD 3 ND 3 ) 2 CuCl 4 is described. In these materials the copper ions, which carry the magnetic moment, are more closely spaced in the ab-planes, and consequently the magnetic interactions in these planes are stronger than those in the direction perpendicular to these planes by about a factor of 10 5 . Chapter 5 presents a discussion and a calculation of demagnetizing and dipole fields. The second part of this thesis is concerned with the transition from the antiferromagnetic to the paramagnetic phase in MnCl 2 .4H 2 O in the presence of a magnetic field applied perpendicular to the preferred direction of the magnetic moments. The theory is reviewed in chapter 6 and in chapter 7 the correction procedure for inhomogeneous internal fields is applied to the measurements on MnCl 2 .4H 2 O. (Auth./C.F.)

  19. Low-temperature heat capacity and thermodynamic properties of [Re2(Ile)4(H2O)8](ClO4)6 (Re=Nd, Er, Ile=isoleucine)

    International Nuclear Information System (INIS)

    Lan Xiaozheng; Tan Zhicheng; Liu Beiping; Nan Zhaodong; Sun Lixian; Xu Fen

    2003-01-01

    The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re 2 (Ile) 4 (H 2 O) 8 ](ClO 4 ) 6 (where Re=Nd, Er, and Ile=isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature range from 80 to 370 K. Two solid-solid phase transitions were found from the C p curve of Nd formed complex in the range of 165-175 K with a peak temperature of 167.88 K and in the range of 195-210 K with a peak temperature of 202.13 K. The corresponding molar enthalpies of these phase transitions were determined to be 404.61 J mol -1 and 2.955 kJ mol -1 , respectively. One solid-solid phase transition was found for the Er formed complex in the range of 190-205 K with a peak temperature of 193.42 K. The corresponding molar enthalpy of this transition was 14.11 kJ mol -1 . Smooth heat capacities and thermodynamic functions relative to the standard state (298.15 K), H T -H 298.15 , S T -S 298.15 and -[G T -G 298.15 ], of the two compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositions for the pair of compounds were suggested according to the thermogravimetric (TG) analysis

  20. Crystal Structure and Spectroscopic Characterization of K8(VO)2O(SO4)6:

    DEFF Research Database (Denmark)

    Rasmussen, Søren Birk; Rasmussen, Rikke Christina; Fehrmann, Rasmus

    2003-01-01

    Red and yellow dichroistic crystals of a vanadium(V) compound, potassium (mu-oxo, di-mu-suifato)bis(oxodisulfato-vanadate), K-8(VO)(2)O(SO4)(6), have been obtained from the ternary catalytic model melt system K2S2O7-K2SO4-V2O5. By slow cooling of the melt from 420 to 355 degreesC, crystal growth...

  1. Synthesis of porous LiFe0.2Mn1.8O4 with high performance for lithium-ion battery

    International Nuclear Information System (INIS)

    Shi, Yishan; Zhu, Shenmin; Zhu, Chengling; Li, Yao; Chen, Zhixin; Zhang, Di

    2015-01-01

    Highlights: • Porous LiFe 0.2 Mn 1.8 O 4 was fabricated with P123 as a template through a nitrate decomposition method • A high rate capacity and cycling stability were demonstrated when used as cathode in LIBs • This strategy is expected to fabricate other multiple metal oxides with porous structures - Abstract: A facile and effective route was developed for the fabrication of LiFe 0.2 Mn 1.8 O 4 with porous structures by using Pluronic P-123 as a soft template, based on a nitrate decomposition method. The resultant LiFe 0.2 Mn 1.8 O 4 was characterized by XRD, SEM, as well as N 2 adsorption/desorption measurements which showed a porous structure with a pore size centered at 20 nm. When used as cathode materials in lithium battery, the as-synthesized LiFe 0.2 Mn 1.8 O 4 exhibited a discharge capacity of 122 mAh g −1 at 1 C and 102 mAh g −1 at 5 C. Moreover, after 500 cycles, the capacity retention (108 mAh g −1 ) reached 88% of the initial capacity at 1 C. As compared with conventional cathode LiMn 2 O 4 , the high performance is believed to originate from the combined effects of porous structure, iron doping and highly crystalline nature of the obtained LiFe 0.2 Mn 1.8 O 4 . This strategy is expected to allow the fabrication of other multiple metal oxides with porous structures for high performance cathode materials

  2. Crystal structure, quantum mechanical investigation, IR and NMR spectroscopy of two new organic salts: (C8H12NO)·[NO3] (I) and (C8H14N4)·[ClO4]2 (II)

    Science.gov (United States)

    Bayar, I.; Khedhiri, L.; Soudani, S.; Lefebvre, F.; Pereira da Silva, P. S.; Ben Nasr, C.

    2018-06-01

    Two new organic-inorganic hybrid materials, 4-methoxybenzylammonium nitrate, (C8H12NO)·[NO3] (I), and 2-(1-piperazinyl)pyrimidinium bis(perchlorate), (C8H14N4)·[ClO4]2(II), have been synthesized by an acid/base reaction at room temperature, their structures were determined by single crystal X-ray diffraction. Compound (I) crystallizes in the orthorhombic system and Pnma space group with a = 15.7908 (7), b = 6.8032 (3), c = 8.7091 (4) Å, V = 935.60 (7) Å3 with Z = 4. Full-matrix least-squares refinement converged at R = 0.038 and wR(F2) = 0.115. Compound (II) belongs to the monoclinic system, space group P21/c with the following parameters: a = 10.798(2), b = 7.330(1), c = 21.186(2) Å, β = 120.641 (4)°, V = 1442.7 (3) Å3and Z = 4. The structure was refined to R = 0.044, wR(F2) = 0.132. In the structures of (I) and (II), the anionic and cationic entities are interconnected by hydrogen bonding contacts forming three-dimensional networks. Intermolecular interactions were investigated by Hirshfeld surfaces and the contacts of the four different chloride atoms in (II) were compared. The Molecular Electrostatic Potential (MEP) maps and the HOMO and LUMO energy gaps of both compounds were computed. The vibrational absorption bands were identified by infrared spectroscopy. These compounds were also investigated by solid-state 13C, 35Cl and 15N NMR spectroscopy. DFT calculations allowed the attribution of the IR and NMR bands.

  3. XPS and EELS characterization of Mn{sub 2}SiO{sub 4}, MnSiO{sub 3} and MnAl{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Grosvenor, A.P., E-mail: andrew.grosvenor@usask.ca [Department of Chemistry, University of Saskatchewan, Saskatoon, SK S7N 5C9 (Canada); Bellhouse, E.M., E-mail: erika.bellhouse@arcelormittal.com [Global R & D—Hamilton, ArcelorMittal Dofasco, 1330 Burlington St. E, Hamilton, ON L8N 3J5 (Canada); Korinek, A., E-mail: korinek@mcmaster.ca [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4M1 (Canada); Bugnet, M., E-mail: bugnetm@mcmaster.ca [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4M1 (Canada); McDermid, J.R., E-mail: mcdermid@mcmaster.ca [Steel Research Centre, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4M1 (Canada)

    2016-08-30

    Graphical abstract: XPS and EELS spectra were acquired from Mn2Al2O4, MnSiO3 and Mn2SiO4 standards and unique features identified that will allow unambiguous identification of these compounds when studying the selective oxidation of advanced steels. - Highlights: • Mn2Al2O4, MnSiO3 and Mn2SiO4 standards were synthesized and characterized using both XPS and EELS. • Unique features in both the XPS high resolution and EELS spectra were identified for all compounds. • The spectra can be used to identify these compounds when studying the selective oxidation of steels. - Abstract: X-ray Photoelectron Spectroscopy (XPS) and Electron Energy Loss Spectroscopy (EELS) are strong candidate techniques for characterizing steel surfaces and substrate-coating interfaces when investigating the selective oxidation and reactive wetting of advanced high strength steels (AHSS) during the continuous galvanizing process. However, unambiguous identification of ternary oxides such as Mn{sub 2}SiO{sub 4}, MnSiO{sub 3}, and MnAl{sub 2}O{sub 4} by XPS or EELS, which can play a significant role in substrate reactive wetting, is difficult due to the lack of fully characterized standards in the literature. To resolve this issue, samples of Mn{sub 2}SiO{sub 4}, MnSiO{sub 3} and MnAl{sub 2}O{sub 4} were synthesized and characterized by XPS and EELS. The unique features of the XPS and EELS spectra for the Mn{sub 2}SiO{sub 4}, MnSiO{sub 3} and MnAl{sub 2}O{sub 4} standards were successfully derived, thereby allowing investigators to fully differentiate and identify these oxides at the surface and subsurface of Mn, Si and Al alloyed AHSS using these techniques.

  4. Magnetic properties and magnetocaloric effects in Mn1.2Fe0.8P1-xGex compounds

    International Nuclear Information System (INIS)

    Ou, Z Q; Wang, G F; Lin Song; Tegus, O; Brueck, E; Buschow, K H J

    2006-01-01

    We have studied the magnetic properties and magnetocaloric effects in the Mn 1.2 Fe 0.8 P 1-x Ge x compounds with x = 0.2, 0.22, 0.3, 0.4 and 0.5. X-ray diffraction patterns show that the Mn 1.2 Fe 0.8 P 1-x Ge x compounds crystallize in the hexagonal Fe 2 P-type crystal structure. The magnetic moments of the Mn 1.2 Fe 0.8 P 1-x Ge x compounds measured at 5 K and 5 T increase with increasing Ge content. The Curie temperature increases strongly and the magnetic entropy change has a maximum around 233 K for the compound with x = 0.22, which is about 19 and 31 J kg -1 K -1 for a field change of 2 and 5 T, respectively

  5. Single-molecule magnets: structure and properties of [Mn18O14(O2CMe)18(hep)4(hepH)2(H2O)2](ClO4)2 with spin S = 13.

    Science.gov (United States)

    Brechin, E K; Sañudo, E C; Wernsdorfer, W; Boskovic, C; Yoo, J; Hendrickson, D N; Yamaguchi, A; Ishimoto, H; Concolino, T E; Rheingold, A L; Christou, G

    2005-02-07

    The reaction of 2-(hydroxyethyl)pyridine (hepH) with a 2:1 molar mixture of [Mn3O(O2CMe)6(py)3]ClO4 and [Mn3O(O2CMe)6(py)3] in MeCN afforded the new mixed-valent (16Mn(III), 2Mn(II)), octadecanuclear complex [Mn18O14(O2CMe)18(hep)4(hepH)2(H2O)2](ClO4)2 (1) in 20% yield. Complex 1 crystallizes in the triclinic space group P. Direct current magnetic susceptibility studies in a 1.0 T field in the 5.0-300 K range, and variable-temperature variable-field dc magnetization studies in the 2.0-4.0 K and 2.0-5.0 T ranges were obtained on polycrystalline samples. Fitting of magnetization data established that complex 1 possesses a ground-state spin of S = 13 and D = -0.18 K. This was confirmed by the value of the in-phase ac magnetic susceptibility signal. Below 3 K, the complex exhibits a frequency-dependent drop in the in-phase signal, and a concomitant increase in the out-of-phase signal, consistent with slow magnetization relaxation on the ac time scale. This suggests the complex is a single-molecule magnet (SMM), and this was confirmed by hysteresis loops below 1 K in magnetization versus dc field sweeps on a single crystal. Alternating current and direct current magnetization data were combined to yield an Arrhenius plot from which was obtained the effective barrier (U(eff)) for magnetization reversal of 21.3 K. Below 0.2 K, the relaxation becomes temperature-independent, consistent with relaxation only by quantum tunneling of the magnetization (QTM) through the anisotropy barrier via the lowest-energy MS = +/-13 levels of the S = 13 spin manifold. Complex 1 is thus the SMM with the largest ground-state spin to display QTM.

  6. Batisivite, V8Ti6[Ba(Si2O)]O28, a new mineral species from the derbylite group

    Science.gov (United States)

    Reznitsky, L. Z.; Sklyarov, E. V.; Armbruster, T.; Galuskin, E. V.; Ushchapovskaya, Z. F.; Polekhovsky, Yu. S.; Karmanov, N. S.; Kashaev, A. A.; Barash, I. G.

    2008-12-01

    , wt %) is: 0.26 Nb2O5, 6.16 SiO2, 31.76 TiO2, 1.81 Al2O3, 8.20 VO2, 26.27 V2O3, 12.29 Cr2O3, 1.48 Fe2O3, 0.08 MgO, 11.42 BaO; the total is 99.73. The VO2/V2O3 ratio has been calculated. The simplified empirical formula is (V{4.8/3+}Cr2.2V{0.7/4+}Fe0.3)8.0(Ti5.4V{0.6/4+})6.0[Ba(Si1.4Al0.5O0.9)]O28. An alternative to the title formula could be a variety (with the diorthogroup Si2O7) V8Ti6[Ba(Si2O7)]O22. Batisivite probably pertains to the V{8/3+}Ti{6/4+}[Ba(Si2O)]O28-Cr{8/3+}Ti{6/4+} [Ba(Si2O)]O28 solid solution series. The type material of batisivite has been deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

  7. Magnon Broadening Effects in Double Layered Manganite La_1.2 Sr_1.8 Mn_2 O_7

    OpenAIRE

    Furukawa, Nobuo; Hirota, Kazuma

    1999-01-01

    Magnon linewidth of La_1.2 Sr_1.8 Mn_2 O_7 near the Brillouin zone boundary is investigated from both theoretical and experimental points of view. Abrupt magnon broadening is ascribed to a strong magnon-phonon coupling. Magnon broadening observed in cubic perovskite manganites is also discussed.

  8. Structure and redox properties of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20 adsorbed on a silica surface. M05 computational study

    Directory of Open Access Journals (Sweden)

    Liudmyla K. Sviatenko

    2016-03-01

    Full Text Available The cluster approximation was applied at M05/tzvp level to model adsorption of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20 on (001 surface of α-quartz. Structures of the obtained CL-20–silica complexes confirm close to parallel orientation of the nitrocompound toward surface. The binding between CL-20 and silica surface was analyzed and bond energies were calculated applying the atoms in molecules (AIM method. Hydrogen bonds were found to significantly contribute in adsorption energy. An attaching of electron leads to significant deviation from coplanarity in complexes and to strengthening of hydrogen bonding. Redox properties of adsorbed CL-20 were compared with those of gas-phase and hydrated species by calculation of electron affinity, ionization potential, reduction Gibbs free energy, oxidation Gibbs free energy, reduction and oxidation potentials. It was shown that adsorbed CL-20 has lower ability to redox transformation as compared with hydrated one.

  9. Crystal structure, quantum mechanical investigation, IR and NMR spectroscopy of two new organic perchlorates: (C6H18N3)·(ClO4)3H2O (I) and (C9H11N2ClO4(II)

    Science.gov (United States)

    Bayar, I.; Khedhiri, L.; Soudani, S.; Lefebvre, F.; Ferretti, V.; Ben Nasr, C.

    2018-06-01

    The reaction of perchloric acid with 1-(2-aminoethyl)piperazine or 5,6-dimethyl-benzimidazole results in the formation of 1-(2-amonioethyl)piperazine-1,4-dium triperchlorate hydrate (C6H18N3)·(ClO4)3·H2O (I) or 5,6-dimethyl-benzylimidazolium perchlorate (C9H11N2ClO4(II). Both compounds were fully structurally characterized including single crystal X-ray diffraction analysis. Compound (I) crystallizes in the centrosymmetric triclinic space group P 1 bar with the lattice parameters a = 7.455 (2), b = 10.462 (2), c = 10.824 (2) Å, α = 80.832 (2), β = 88.243 (2), γ = 88.160 (2) °, Z = 2 and V = 832.77 (3) Å3. Compound (II) has been found to belong to the P21/c space group of the monoclinic system, with a = 7.590 (3), b = 9.266 (3), c = 16.503 (6) Å, β = 107.38 (2) °, V = 1107.69 (7) Å3 and Z = 4. The structures of (I) and (II) consist of slightly distorted [ClO4]- tetrahedra anions and 1-(2-amonioethyl)piperazine-1,4-dium trication (I) or 5,6-dimethyl-benzylimidazolium cations (II) and additionally a lattice water in (I). The crystal structures of (I) and (II) exhibit complex three-dimensional networks of H-bonds connecting all their components. In the atomic arrangement of (I), the ClO4- anions form corrugated chains, while in (II) the atomic arrangement exhibits wide pseudo-hexagonal channels of ClO4 tetrahedra including the organic entities. The lattice water serves as a link between pairs of cations and pairs of anions via several Osbnd H⋯O and N-H⋯O interactions in compound (I). The vibrational absorption bands were identified by infrared spectroscopy. These compounds were also investigated by solid-state 13C, 35Cl and 15N NMR spectroscopy. DFT calculations allowed the attribution of the IR and NMR bands. Intermolecular interactions were investigated by Hirshfeld surfaces. Electronic properties such as HOMO and LUMO energies were derived.

  10. (μ-3-Acetyl-5-carboxyl­ato-4-methyl­pyrazolido-1:2κ4 N 2,O 3:N 1,O 5)-μ-chlorido-tetra­pyridine-1κ2 N,2κ2 N-chlorido-1κCl-dicopper(II) propan-2-ol solvate

    Science.gov (United States)

    Malinkin, Sergey; Penkova, Larisa; Pavlenko, Vadim A.; Haukka, Matti; Fritsky, Igor O.

    2009-01-01

    The title compound, [Cu2(C7H6N2O3)Cl2(C5H5N)4]·C3H8O, is a binuclear pyrazolate complex, in which the two CuII atoms have different coordination numbers and are connected by a bridging Cl atom. One CuII atom has a distorted square-pyramidal coordination environment formed by two pyridine N atoms, one bridging Cl atom and an N,O-chelating pyrazolate ligand. The other CuII atom adopts an octa­hedral geometry defined by two pyridine N atoms at the axial positions, two Cl atoms and the coordinated pyrazolate ligand in the equatorial plane. An O—H⋯O hydrogen bond connects the complex mol­ecules and propan-2-ol solvent mol­ecules into pairs. These pairs form columns along the a axis. PMID:21577764

  11. Synthesis and luminescent properties of Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26} oxyapatites

    Energy Technology Data Exchange (ETDEWEB)

    Ishchenko, A.V., E-mail: a-v-i@mail.ru [Ural Federal University, 620002 Ekaterinburg (Russian Federation); Zuev, M.G. [Ural Federal University, 620002 Ekaterinburg (Russian Federation); Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg (Russian Federation); Vasin, A.A. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, 620990 Ekaterinburg (Russian Federation); Yagodin, V.V.; Viktorov, L.V.; Shulgin, B.V. [Ural Federal University, 620002 Ekaterinburg (Russian Federation)

    2016-01-15

    The solid solutions Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26−δ} (where x=0–0.15 and δ is oxygen nonstoichiometry) were synthesized. The structural properties of the crystal lattice of the solid solutions and the peculiarities of Eu{sup 3+} and P{sup 5+} dopants substitution for matrix ions have been considered. The photo-, X-ray and pulsed cathode luminescence properties have been studied. It has been found that substitution of (SiO{sub 4}){sup 4−} by (PO{sub 4}){sup 3−} tetrahedron in Eu{sup 3+}-doped oxyapatites does not bring significant changes to bands structure Eu{sup 3+} in luminescence spectra under different excitation (UV, X-ray, pulse cathode beam). However, the increase of P{sup 5+} concentration in Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26–δ} compounds leads to a decrease of integral intensity of Eu{sup 3+} luminescence bands due to local environment symmetry modifications and covalency degree changes. Two nonequivalent optical Eu{sup 3+} centers have been found. These compounds are of interest for efficient X-ray phosphors, display devices and LED engineering material creation. - Highlights: • The luminescence properties were studied upon UV, X-ray and pulse cathode beam. • P{sup 5+} doping of Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6}O{sub 26} leads to luminescence intensity reduction. • At least two types of optical centers formed by Eu{sup 3+} ions were found. • The structural features of Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6(1−x)}P{sub 6x}O{sub 26} were reported. • Partial replacement of Si by P does not change the Sr{sub 2}Gd{sub 6.8}Eu{sub 1.2}Si{sub 6}O{sub 26} structure.

  12. Enhancement of magnetoresistance and ferromagnetic coupling in the complex perovskites CaCu{sub 3}(Mn{sub 4−x}Al{sub x})O{sub 12} (x = 0, 0.2, 0.4, and 0.6): A neutron diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Ben Hassine, R.; Cherif, W. [Faculty of Sciences, Sfax University, Sfax, B.P. 1171-3000 (Tunisia); Sánchez-Benítez, J. [Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Mompean, F. J.; Alonso, J. A., E-mail: ja.alonso@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas, Cantoblanco, E-28049 Madrid (Spain); Fernández-Díaz, M. T. [Institut Laue-Langevin, B.P. 156, F-38042 Grenoble Cedex 9 (France); Elhalouani, F. [National School of Engineers, Sfax University, Sfax, B.P. W 3038 (Tunisia)

    2015-09-14

    New compounds of the series CaCu{sub 3}(Mn{sub 4−x}Al{sub x})O{sub 12} have been prepared under high pressure conditions (2 GPa), in the presence of KClO{sub 4} as oxidizing agent to stabilize Mn{sup 3+,4+} mixed valence. The polycrystalline samples have been characterized by x-ray diffraction, neutron powder diffraction (NPD), magnetic, and magnetotransport measurements. All the samples are cubic, space group Im-3. These oxides adopt a superstructure of ABO{sub 3} perovskite given by the long-range 1:3 ordering of Ca{sup 2+} and Cu{sup 2+} ions at the A sublattice. The NPD study for x = 0.4 shows that Al{sup 3+} ions are statistically distributed at the octahedral positions, being the (Mn,Al)O{sub 6} octahedra strongly tilted, with superexchange (Mn,Al)-O-(Mn,Al) angles of 142.1°. Also, neutron data clearly show that some Mn{sup 3+} ions (0.65(2) per formula) are located together with Cu{sup 2+} at the square-planar 6b positions. Regarding the magnetic properties, all the compounds present a spontaneous increase of the magnetization below T{sub C}, typical of ferro-or ferrimagnetic materials, with T{sub C} decreasing upon Al introduction. The magnetic structure determined from low-temperature NPD data unveils a ferromagnetic coupling between (Cu{sup 2+}, Mn{sup 3+}){sub 6b} spins and Mn{sub 8c} spins at octahedral positions; this is in contrast with the ferrimagnetic structure observed for RCu{sub 3}Mn{sub 4}O{sub 12} and CaCu{sub 3}Mn{sub 4}O{sub 12}, where an AFM coupling is observed between both magnetic sublattices. Interestingly, an enhancement of the magnetoresistance effect is observed for x = 0.2, well beyond that found for the parent compound. This effect, in materials subtly doped with non-magnetic elements at the Mn positions, may be of interest for applications.

  13. 3-D MnNb{sub 2}O{sub 6} nanogears from 1-D Nb{sub 2}O{sub 5} nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Hu Weibing, E-mail: w.hu@tom.com [School of Chemical and Environmental Engineering, Hubei Institute for Nationalities, Enshi 445000 (China); Cui Zhicai [School of Chemical and Environmental Engineering, Hubei Institute for Nationalities, Enshi 445000 (China); Mi Yuanzhu [School of Chemistry and Environmental Engineering, Yangtze University, Nanhuan Road 1, Jingzhou 434023 (China)

    2012-04-16

    Graphical abstract: The geometry morphology of Nb-based nanomaterial evolved from long Nb{sub 2}O{sub 5} nanorods to a mixture of short Nb{sub 2}O{sub 5} nanorods and MnNb{sub 2}O{sub 6} 6-teeth nanogears, and eventually to fully developed pure 3-D nanogears. Highlights: Black-Right-Pointing-Pointer MnNb{sub 2}O{sub 6} nanogears have been generated by a simple solvothermal process when the Mn: Nb ratio was 1:1. Black-Right-Pointing-Pointer MnNb{sub 2}O{sub 6} 6-teeth nanogears accompanied with MnNb{sub 2}O{sub 6} 5-teeth nanogears are got when the Mn:Nb ratio reached 1:2. Black-Right-Pointing-Pointer The nanomaterial consists of nanorods and 6-teeth nanogears at low Mn:Nb molar ratio(1:4). Black-Right-Pointing-Pointer Pure long Nb{sub 2}O{sub 5} nanorods are achieved by only using NbCl{sub 5} - Abstract: MnNb{sub 2}O{sub 6} nanogears have been generated by using mixed NbCl{sub 5} and MnCl{sub 2} at an optimized ratio of 1:1 in a cyclohexanol solvent in a simple solvothermal process. It has shown that the Mn:Nb ratio determines the shape of the products. Detailed characterization by electron microscopy has shown that increasing the Mn{sup +2} concentration during the solvo-thermal synthesis promotes a morphological evolution from relatively long Nb{sub 2}O{sub 5} nanorods to a mixture of short Nb{sub 2}O{sub 5} nanorods and MnNb{sub 2}O{sub 6} 6-teeth nanogears, then to a mixture of short Nb{sub 2}O{sub 5} nanorods and more MnNb{sub 2}O{sub 6} 6-teeth nanogears, then to more and more MnNb{sub 2}O{sub 6} 6-teeth nanogears that are occasionally accompanied with under-developed MnNb{sub 2}O{sub 6} 5-teeth nanogears, and eventually to fully developed pure 3-D nanogears. The driving force for such interesting geometry transformations is attributed to the inclusion of Mn{sup 2+} into the Nb{sub 2}O{sub 5} template at low Mn{sup 2+} concentrations, which introduces internal stresses to the Nb{sub 2}O{sub 5} nanorods. At high Mn{sup 2+} concentrations, close to the

  14. Molecular dynamics simulations of spinels: LiMn2O4 and Li4Mn5O12 at high temperatures

    International Nuclear Information System (INIS)

    Ledwaba, R S; Matshaba, M G; Ngoepe, P E

    2015-01-01

    Energy storage technologies are critical in addressing the global challenge of clean sustainable energy. Spinel lithium manganates have attracted attention due to their electrochemical properties and also as promising cathode materials for lithium-ion batteries. The current study focused on the effects of high temperatures on the materials, in order to understand the sustainability in cases where the battery heats up to high temperature and analysis of lithium diffusion aids in terms of intercalation host compatibility. It is also essential to understand the high temperature behaviour and lithium ion host capability of these materials in order to perform the armorphization and recrystalization of spinel nano-architectures. Molecular dynamics simulations carried out to predict high temperature behaviour of the spinel systems. The NVE ensemble was employed, in the range 300 - 3000K. The melting temperature, lithium-ion diffusion and structural behaviour were monitored in both supercell systems. LiMn 2 O 4 indicated a diffusion rate that increased rapidly above 1500K, just before melting (∼1700K) and reached its maximum diffusion at 2.756 × 10 -7 cm 2 s -1 before it decreased. Li 4 Mn 5 O 12 indicated an exponential increase above 700K reaching 8.303 × 10 −7 cm 2 s −1 at 2000K and allowing lithium intercalation even above its melting point of around 1300K. This indicated better structural stability of Li 4 Mn 5 O 12 and capability to host lithium ions at very high temperatures (up to 3000 K) compared to LiMn 2 O 4 . (paper)

  15. Ion-beam-driven amorphization of Ca2La8(SiO4)6O2 single crystals

    International Nuclear Information System (INIS)

    Weber, W.J.; Hess, N.J.; Wang, L.M.

    1993-11-01

    Single crystals of Ca 2 La 8 (SiO 4 ) 6 O 2 , with 1% Nd substituted for La, were irradiated with 0.8 MeV Ne + and 1.5 MeV Kr + ions from 15 to 773 K. The irradiations were carried out using the HVEM-Tandem Facility at Argonne National Laboratory. The structural changes and the ion fluence for complete amorphization were determined by in situ transmission electron microscopy. The ion fluence for complete amorphization increased with temperature in two stages associated with defect annealing processes. The critical temperature for amorphization increased from ∼360 K for 0.8 MeV Ne + to ∼710 K for 1.5 MeV Kr + . During in situ annealing studies, irradiation-enhanced recrystallization was observed at 923 K. Spatially-resolved fluorescence spectra of the Nd ion excited with 488.0 mn laser excitation showed marked line-broadening toward the center of the amorphous regions. Initial measurements indicate the subtle shifts of the 9 I 9/2 groundstate energy levels can be measured by pumping directly into the excited state 4 F 3/2 manifold suggesting that the line broadening observed originates from a distribution of geometrically distorted Nd sites

  16. Hydrothermal synthesis and crystal structure of the Ni2(C4H4N2)(V4O12)(H2O)2 and Ni3(C4H4N2)3(V8O23) inorganic-organic hybrid compounds. Thermal, spectroscopic and magnetic studies of the hydrated phase

    International Nuclear Information System (INIS)

    Larrea, Edurne S.; Mesa, Jose L.; Pizarro, Jose L.; Arriortua, Maria I.; Rojo, Teofilo

    2007-01-01

    Ni 2 (C 4 H 4 N 2 )(V 4 O 12 )(H 2 O) 2 , 1, and Ni 3 (C 4 H 4 N 2 ) 3 (V 8 O 23 ), 2, have been synthesized using mild hydrothermal conditions at 170 deg. C under autogenous pressure. Both phases crystallize in the P-1 triclinic space group, with the unit-cell parameters, a=7.437(7), b=7.571(3), c=7.564(4) A, α=65.64(4), β=76.09(4), γ=86.25(3) o for 1 and a=8.566(2), b=9.117(2), c=12.619(3) A, α=71.05(2), β=83.48(4), γ=61.32(3) o for 2, being Z=2 for both compounds. The crystal structure of the three-dimensional 1 is constructed from layers linked between them through the pyrazine molecules. The sheets are formed by edge-shared [Ni 2 O 6 (H 2 O) 2 N 2 ] nickel(II) dimers octahedra and rings composed by four [V 4 O 12 ] vanadium(V) tetrahedra linked through vertices. The crystal structure of 2 is formed from vertex shared [VO 4 ] tetrahedra that give rise to twelve member rings. [NiO 4 (C 4 H 4 N 2 ) 2 ] ∞ chains, resulting from [NiO 4 N 2 ] octahedra and pyrazine molecules, give rise to a 3D skeleton when connecting to [VO 4 ] tetrahedra. Diffuse reflectance measurements of 1 indicate a slightly distorted octahedral geometry with values of Dq=880, B=980 and C=2700 cm -1 . Magnetic measurements of 1, carried out in the 5.0-300 K range, indicate the existence of antiferromagnetic couplings with a Neel temperature near to 38 K. - Graphical abstract: Crystal structure of a sheet of Ni 2 (C 4 H 4 N 2 )(V 4 O 12 )(H 2 O) 2

  17. 2,6-Diaminopyridinium bis(4-hydroxypyridine-2,6-dicarboxylato-κ3O2,N,O6ferrate(III dihydrate

    Directory of Open Access Journals (Sweden)

    Andya Nemati

    2008-10-01

    Full Text Available The reaction of iron(II sulfate heptahydrate with the proton-transfer compound (pydaH(hypydcH (pyda = pyridine-2,6-diamine; hypydcH2 = 4-hydroxypyridine-2,6-dicarboxylic acid in an aqueous solution led to the formation of the title compound, (C5H8N3[Fe(C7H3NO52]·2H2O. The anion is a six-coordinated complex with a distorted octahedral geometry around the FeIII atom. Extensive intermolecular O—H...O, N—H...O and C—H...O hydrogen bonds, involving the complex anion, (pydaH+ counter-ion and two uncoordinated water molecules, and π–π [centroid-to-centroid distance 3.323 (11 Å] and C—O...π [O–centroid distance 3.150 (15 Å] interactions connect the various components into a supramolecular structure.

  18. (2,4-Dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylato-κ2O4,O5(4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylato-κ2O4,O5bis(1,10-phenanthroline-κ2N,N′yttrium(III dihydrate

    Directory of Open Access Journals (Sweden)

    Zilu Chen

    2008-09-01

    Full Text Available In the title compound, [Y(C5H2N2O4(C5H3N2O4(C12H8N22]·2H2O, the YIII ion lies on a twofold rotation axis and exhibits a distorted square-antiprismatic coordination geometry. It is chelated by two 1,10-phenanthroline ligands, a 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate monoanion and a 4-oxido-2-oxo-1,2-dihydropyrimidine-5-carboxylate dianion. The H atom involved in an N—H...N hydrogen bond between the 1,2-dihydropyrimidine units has half occupancy and is disordered around a twofold rotation axis.

  19. MCD spectroscopy of hexanuclear Mn(III) salicylaldoxime single-molecule magnets.

    Science.gov (United States)

    Bradley, Justin M; Thomson, Andrew J; Inglis, Ross; Milios, Constantinos J; Brechin, Euan K; Piligkos, Stergios

    2010-11-07

    The hexanuclear cages [Mn(6)O(2)(R-sao)(6)L(2)(EtOH)(x)(H(2)O)(y)] "Mn(6)" behave as single-molecule magnets (SMMs) below a characteristic blocking temperature. As with [Mn(12)O(12)(O(2)CR)(16)(H(2)O)(4)] "Mn(12)" the electronic absorption spectra are rather featureless, yielding little information on the electronic structure of the magnetic ions. Low temperature Magnetic Circular Dichroism (MCD) spectra afford greater resolution of the optical transitions and also probe the magnetic properties of the system. Both the ground state spin and blocking temperature of the Mn(6) cages are determined by subtle structural perturbations of a generic Mn(6)O(2) core. Absorbance and MCD spectra are reported for [Mn(6)O(2)(Et-sao)(6){O(2)CPh(Me)(2)}(2)(EtOH)(6)] (1), [Mn(6)O(2)(Et-sao)(6){O(2)CPh}(2)(EtOH)(4)(H(2)O)(2)] (2), [Mn(6)O(2)(sao)(6){O(2)CPh}(2)(EtOH)(4)]·EtOH (3) and the trinuclear precursor [Mn(3)O(Et-sao)(3)(MeOH)(3)](ClO(4)) (4) cast into polymer film. SMM behaviour has previously been observed using magnetic susceptibility measurements on powder and single-crystal samples. The ligand field environment of the magnetic ions is assumed to be similar in (1) and (2) and their different blocking temperatures are attributed to the magnitude of the effective exchange constant. The MCD spectra of (1) and (2), in which the ground state spin S = 12, show that the ligand field environments of the Mn ions are almost identical and that magnetic hysteresis persists for isolated molecules when crystal packing forces are removed. The subtle structural differences between (1) and (2) are manifested in the field dependence of the MCD response at different wavelengths that reflect changes in band polarisation. The MCD spectrum of (3) contains features not apparent in those of (1) and (2). These are attributed to 5-coordinate Mn(iii), which is unique to (3) among the compounds studied. (3) has ground state spin S = 4, a lower blocking temperature and consequently no observable

  20. Microstructure, crystal structure and electrical properties of Cu0.1Ni0.8Co0.2Mn1.9O4 ceramics obtained at different sintering conditions

    International Nuclear Information System (INIS)

    Bodak, O.; Akselrud, L.; Demchenko, P.; Kotur, B.; Mrooz, O.; Hadzaman, I.; Shpotyuk, O.; Aldinger, F.; Seifert, H.; Volkov, S.; Pekhnyo, V.

    2002-01-01

    Details of the formation of Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 ceramics under different sintering conditions have been studied by optical microscopy, scanning electron microscopy (SEM), electron probe and energy dispersive spectroscopy (EDX) microanalyses, X-ray diffraction (XRD) and electrical resistivity measurements. Microstructure studies of samples sintered at 1170 deg. C for 1 h indicated the presence of a secondary phase besides the main spinel phase with modified composition. XRD measurements showed that the spinel phase exhibits a tetragonally distorted spinel structure (space group I4 1 /amd, a=5.9410(5) A, c=8.4196(15) A). The secondary phase (solid solution based on NiO) crystallizes with the NaCl-type structure (space group Fm3-bar m, a=4.1872(3) A). The content of the secondary phase in ceramics is 10.61 mass%. For NiMn 2 O 4 ceramics, prepared under the same sintering conditions, the decomposition with Ni 1-x Mn x O solid solution (NaCl-type structure) and spinel phase formation have been observed. The tetragonal modification of the spinel phase for NiMn 2 O 4 ceramics is more preferable (space group I4 1 /amd, a=5.9764(5) A, c=8.4201(8) A). The distribution of atoms in the structure has been proposed for both ceramics. According to XRD results the Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 ceramic samples, sintered at 920 deg. C for 8 h (program 1), at 920 deg. C for 8 h and at 750 deg. C for 24 h (program 2), at 920 deg. C for 8 h, at 1200 deg. C for 1 h and at 920 deg. C for 24 h (program 3) and at 920 deg. C for 8 h, at 1200 deg. C for 1 h, at 920 deg. C for 24 h and at 750 deg. C for 48 h (program 4), contain a single phase with the cubic spinel structure (space group Fd3-bar m). Small residuals of the secondary phase for the ceramics, prepared via programs 3 and 4, have been observed by SEM investigations. The structure transformations of the spinel phase for Cu 0.1 Ni 0.8 Co 0.2 Mn 1.9 O 4 ceramics sintered at 1170 deg. C are attributed to a Jahn

  1. α-ScVSe2O8, β-ScVSe2O8, and ScVTe2O8: new quaternary mixed metal oxides composed of only second-order Jahn-Teller distortive cations.

    Science.gov (United States)

    Kim, Yeong Hun; Lee, Dong Woo; Ok, Kang Min

    2013-10-07

    Three new quaternary scandium vanadium selenium/tellurium oxides, α-ScVSe2O8, β-ScVSe2O8, and ScVTe2O8 have been synthesized through hydrothermal and standard solid-state reactions. Although all three reported materials are stoichiometrically similar, they exhibit different crystal structures: α-ScVSe2O8 has a three-dimensional framework structure consisting of ScO6, VO6, and SeO3 groups. β-ScVSe2O8 reveals another three-dimensional framework composed of ScO7, VO5, and SeO3 polyhedra. ScVTe2O8 shows a layered structure with ScO6, VO4, and TeO4 polyhedra. Interestingly, the constituent cations, that is, Sc(3+), V(5+), Se(4+), and Te(4+) are all in a distorted coordination environment attributable to second-order Jahn-Teller (SOJT) effects. Complete characterizations including infrared spectroscopy, elemental analyses, thermal analyses, dipole moment calculation, and the magnitudes of out-of-center distortions for the compounds are reported. Transformation reactions suggest that α-ScVSe2O8 may change to β-ScVSe2O8, and then to Sc2(SeO3)3·H2O under hydrothermal conditions.

  2. A novel bilayered Sr{sub 0.6}La{sub 0.4}TiO{sub 3}/La{sub 0.8}Sr{sub 0.2}MnO{sub 3} interconnector for anode-supported tubular solid oxide fuel cell via slurry-brushing and co-sintering process

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yanjie; Wang, Shaorong; Liu, Renzhu; Wen, Tinglian; Wen, Zhaoyin [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

    2011-02-01

    Considering that conventional lanthanum chromate (LaCrO{sub 3}) interconnector is hard to be co-sintered with green anode, we have fabricated a novel bilayered interconnector which consists of La-doped SrTiO{sub 3} (Sr{sub 0.6}La{sub 0.4}TiO{sub 3}) and Sr-doped lanthanum manganite (La{sub 0.8}Sr{sub 0.2}MnO{sub 3}). Sr{sub 0.6}La{sub 0.4}TiO{sub 3} is conductive and stable in reducing atmosphere, locating on the anode side; while La{sub 0.8}Sr{sub 0.2}MnO{sub 3} is on the cathode side. A slurry-brushing and co-sintering method is applied: the Sr{sub 0.6}La{sub 0.4}TiO{sub 3} and La{sub 0.8}Sr{sub 0.2}MnO{sub 3} slurries are successively brushed onto green anode specimen, followed by co-firing course to form a dense bilayered Sr{sub 0.6}La{sub 0.4}TiO{sub 3}/La{sub 0.8}Sr{sub 0.2}MnO{sub 3} interconnector. For operating with humidified hydrogen and oxygen at 900 C, the ohmic resistances between anode and cathode/interconnector are 0.33 {omega} cm{sup 2} and 0.186 {omega} cm{sup 2}, respectively. The maximum power density is 290 mW cm{sup -2} for a cell with interconnector, and 420 mW cm{sup -2} for a cell without it, which demonstrates that nearly 70% of the power output can be achieved using this bilayered Sr{sub 0.6}La{sub 0.4}TiO{sub 3}/La{sub 0.8}Sr{sub 0.2}MnO{sub 3} interconnector. (author)

  3. Octa-akis(4-amino-pyridine)-1κN,2κN-aqua-2κO-μ-carbonato-1:2κO,O':O''-dinickel(II) dichloride penta-hydrate.

    Science.gov (United States)

    Fun, Hoong-Kun; Sinthiya, A; Jebas, Samuel Robinson; Ravindran Durai Nayagam, B; Alfred Cecil Raj, S

    2008-10-18

    In the title compound, [Ni(2)(CO(3))(C(5)H(6)N(2))(8)(H(2)O)]Cl(2)·5H(2)O, one of the the Ni(II) ions is six-coordinated in a distorted octa-hedral geometry, with the equatorial plane defined by four pyridine N atoms from four amino-pyridine ligands, the axial positions being occupied by one water O and a carbonate O atom. The other Ni(II) ion is also six-coordinated, by four other pyridine N atoms from four other amino-pyridine ligands and two carbonate O atoms to complete a distorted octa-hedral geometry. In the crystal structure, mol-ecules are linked into an infinite three-dimensional network by O-H⋯O, N-H⋯Cl, N-H⋯O, O-H⋯N, C-H⋯O, C-H⋯N and C/N-H⋯π inter-actions involving the pyridine rings.

  4. Properties of Mn0.4Zn0.6Fe2O4 and Mn0.6Zn0.4Fe2O4 as Nanocatalyst for Ammonia Production

    Directory of Open Access Journals (Sweden)

    Puspitasari Poppy

    2017-01-01

    Full Text Available Ammonia synthesis requires high pressure and high temperature process. Unfortunately, the capital intensive cost resulting low yield of ammonia by using recent catalyst which is iron oxide. Therefore, manganese zinc ferrite as a soft ferrite material will be introduced as a new nanocatalyst to enhance the ammonia yield. As a new nanocatalyst for ammonia production, study of comparasion two different concentration of MnZn Ferrite is very important. This paper will compare the yield of ammonia by using two different nanocatalyst which are Mn0.4Zn0.6Fe2O4 and Mn0.6Zn0.4Fe2O4. Both were synthesized by sol-gel method and has been characterize by using FESEM (morphology, XRD (phase identification, EDX (elemental analysis and TPR (oxide reduction. The ammonia was produce with and without magnetic field applied. The result shows that the ammonia yield is higher for Mn0.4Zn0.6Fe2O4 nanocatalyst than Mn0.6Zn0.4Fe2O4 by using magnetic field applied. 67.2% of yield has been achieved by using new nanocatalyst Mn0.6Zn0.4Fe2O4 and magnetic field applied at ambient environment.

  5. Propane-1,3-diammonium bis[aquachlorido(4-hydroxypyridine-2,6-dicarboxylato-κ3O2,N,O6mercurate(II] tetrahydrate

    Directory of Open Access Journals (Sweden)

    Hossein Aghabozorg

    2008-08-01

    Full Text Available The reaction of mercury(II chloride dihydrate, propane-1,3-diamine and 4-hydroxypyridine-2,6-dicarboxylic acid in a 1:1:1 molar ratio in aqueous solution, resulted in the formation of the title compound, (C3H12N2[Hg(C7H3NO5Cl(H2O]2·4H2O or (pnH2[Hg(hypydcCl(H2O]2·4H2O (where pn is propane-1,3-diamine and hypydcH2 is 4-hydroxypyridine-2,6-dicarboxylic acid. The metal atom is coordinated by one chloride group, one water molecule cis to the chloride ligand and one (hypydc2− ligand. The coordinated water molecule is almost perpendicular to the plane of the aromatic ring of (hypydc2−. The geometry of the resulting HgClNO3 coordination can be described as distorted square-pyramidal. This structure also contains propane-1,3-diammonium (site symmetry 2 as a counter-ion and four uncoordinated water molecules. There is a wide range of non-covalent interactions consisting of hydrogen bonding [of the types O—H...O, N—H...O and C—H...O, with D...A ranging from 2.548 (5 to 3.393 (6 Å] and ion pairing.

  6. Crystal structure of 2-amino-4-(4-chlorophenyl-1-(4-methylphenyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carbonitrile

    Directory of Open Access Journals (Sweden)

    Shaaban K. Mohamed

    2015-12-01

    Full Text Available In the title compound, C23H20ClN3O, each of the cyclohexene and 1,4-dihydropyridine rings of the 1,4,5,6,7,8-hexahydroquinoline ring system adopts a twisted-boat conformation. The dihedral angle between the two benzene rings is 11.52 (7°. In the crystal, molecules are linked through a pair of amino–nitrile N—H...N hydrogen bonds, forming inversion dimers. These assemble into a three-dimensional network via C—H...O and C—H...π interactions.

  7. Propane-1,2-diammonium bis(pyridine-2,6-dicarboxylato-κ3O,N,O′nickelate(II tetrahydrate

    Directory of Open Access Journals (Sweden)

    Mohammad Ghadermazi

    2008-07-01

    Full Text Available The reaction of nickel(II nitrate hexahydrate, propane-1,2-diamine and pyridine-2,6-dicarboxylic acid in a 1:2:2 molar ratio in aqueous solution resulted in the formation of the title compound, (C3H12N2[Ni(C7H3NO42]·4H2O or (p-1,2-daH2[Ni(pydc24H2O (where p-1,2-da is propane-1,2-diamine and pydcH2 is pyridine-2,6-dicarboxylic acid. The geometry of the resulting NiN2O4 coordination can be described as distorted octahedral. Considerable C=O...π stacking interactions are observed between the carboxylate C=O groups and the pyridine rings of the (pydc2− fragments, with O...π distances of 3.1563 (12 and 3.2523 (12 Å and C=O...π angles of 95.14 (8 and 94.64 (8°. In the crystal structure, a wide range of non-covalent interactions, consisting of hydrogen bonding [O—H...O, N—H...O and C—H...O, with D...A distances ranging from 2.712 (2 to 3.484 (2 Å], ion pairing, π–π [centroid-to-centroid distance = 3.4825 (8 Å] and C=O...π stacking, connect the various components to form a supramolecular structure.

  8. Interfacial reactions of Ba 2YCu 3O 6+z with coated conductor buffer layer, LaMnO 3

    Science.gov (United States)

    Liu, G.; Wong-Ng, W.; Kaduk, J. A.; Cook, L. P.

    2010-03-01

    Chemical interactions between the Ba 2YCu 3O 6+x superconductor and the LaMnO 3 buffer layers employed in coated conductors have been investigated experimentally by determining the phases formed in the Ba 2YCu 3O 6+x-LaMnO 3 system. The Ba 2YCu 3O 6+x-LaMnO 3 join within the BaO-(Y 2O 3-La 2O 3)-MnO 2-CuO x multi-component system is non-binary. At 810 °C ( pO2 = 100 Pa) and at 950 °C in purified air, four phases are consistently present along the join, namely, Ba 2-x(La 1+x-yY y)Cu 3O 6+z, Ba(Y 2-xLa x)CuO 5, (La 1-xY x)MnO 3, (La,Y)Mn 2O 5. The crystal chemistry and crystallography of Ba(Y 2-xLa x)CuO 5 and (La 1-xY x)Mn 2O 5 were studied using the X-ray Rietveld refinement technique. The Y-rich and La-rich solid solution limits for Ba(Y 2-xLa x)CuO 5 are Ba(Y 1.8La 0.2)CuO 5 and Ba(Y 0.1La 1.9)CuO 5, respectively. The structure of Ba(Y 1.8La 0.2)CuO 5 is Pnma (No. 62), a = 12.2161(5) Å, b = 5.6690(2) Å, c = 7.1468(3) Å, V = 494.94(4) Å 3, and D x = 6.29 g cm -3. YMn 2O 5 and LaMn 2O 5 do not form solid solution at 810 °C ( pO2 = 100 Pa) or at 950 °C (in air). The structure of YMn 2O 5 was confirmed to be Pbam (No. 55), a = 7.27832(14) Å, b = 8.46707(14) Å, c = 5.66495(10) Å, and V = 349.108(14) Å 3. A reference X-ray pattern was prepared for YMn 2O 5.

  9. The synthesis and crystal structures of the first rare-earth alkaline-earth selenite chlorides MNd10(SeO3)12Cl8 (M=Ca and Sr)

    International Nuclear Information System (INIS)

    Berdonosov, P.S.; Olenev, A.V.; Dolgikh, V.A.; Lightfoot, P.

    2007-01-01

    Two new alkaline-earth Nd selenite chlorides MNd 10 (SeO 3 ) 12 Cl 8 (M=Ca, Sr) were obtained using crystal growth from alkaline-earth chloride melts in quartz tubes. These new compounds crystallize in the orthorhombic system in space group C cca (no. 68). The compounds were studied by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction. It was shown that both compounds adopt the same structure type, constructed by complex [M 11 (SeO 3 ) 12 ] 8+ slabs separated by chloride anion layers perpendicular to the longest cell parameter. The SeO 3 groups show a pyramidal shape and may be described as SeO 3 E tetrahedra. Such SeO 3 groups decorate the Nd-O skeletons forming the [M 11 (SeO 3 ) 12 ] 8+ slabs. - Graphical abstract: Two new alkaline-earth Nd selenite chlorides MNd 10 (SeO 3 ) 12 Cl 8 (M=Ca, Sr) were synthesized. These structures are constructed by [M 11 (SeO 3 ) 12 ] 8+ slabs separated by chloride anion layers

  10. 3-[(R-3,3-Dichloro-2-hydroxypropyl]-8-hydroxy-6-methoxy-1H-isochromen-1-one

    Directory of Open Access Journals (Sweden)

    Yong-Cheng Lin

    2008-09-01

    Full Text Available The title compound, C13H12Cl2O5, is an isocoumarin compound which has been isolated from the ethyl acetate extract of the fermentation broth of actinomycete Streptomyces sp. (V4 from the South China Sea. There are intra- and intermolecular hydrogen bonds and halogen bonds [Cl...Cl = 3.434 (2 Å; C—Cl...Cl = 121.6°]. The intermolecular O—H...O hydrogen bonds link molecules into chains along the b axis.

  11. (1R,4R,6S,7R-5,5-Dibromo-1,4,8,8-tetramethyltricyclo[5.4.1.04,6]dodecan-12-one

    Directory of Open Access Journals (Sweden)

    Mohamed Zaki

    2014-05-01

    Full Text Available The title compound, C16H24Br2O, was synthesized from the reaction of β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene, which was isolated from Atlas cedar (Cedrus atlantica. The asymmetric unit contains two independent molecules with similar conformations. Each molecule is built up from two fused seven-membered rings and an additional three-membered ring. In both molecules, one of the seven-membered rings has a chair conformation, whereas the other displays a screw-boat conformation.

  12. Mechanochemical synthesis and crystal structure of a 1:2 co-crystal of 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecane (TATU and 4-chloro-3,5-dimethylphenol

    Directory of Open Access Journals (Sweden)

    Augusto Rivera

    2016-11-01

    Full Text Available Solvent-free treatment of 1,3,6,8-tetraazatricyclo[4.3.1.13,8]undecano (TATU with 4-chloro-3,5-dimethylphenol led to the formation of the title co-crystal, C7H14N4·2C8H9ClO. The asymmetric unit contains one aminal cage molecule and two phenol molecules linked via two O—H...N hydrogen bonds. In the aminal cage, the N–CH2–CH2–N unit is slightly distorted from a syn periplanar geometry. Aromatic π–π stacking between the benzene rings from two different neighbouring phenol molecules [centroid–centroid distance = 4.0570 (11 Å] consolidates the crystal packing.

  13. Bis{μ-2,2′-[1,1′-(ethane-1,2-diyldinitrilodiethylidyne]diphenolato-κ5O,N,N′,O′:O}bis[chloridomanganese(III

    Directory of Open Access Journals (Sweden)

    Robert D. Pike

    2008-02-01

    Full Text Available The title compound, [Mn2(C18H18N2O22Cl2], was synthesized by the reaction between manganese(II o-chlorobenzoate and the Schiff base generated in situ by the condensation of ethane-1,2-diamine and o-hydroxyacetophenone. The centrosymmetric dimer contains two Jahn–Teller-distorted manganese(III ions, each in an octahedral geometry, connected through two phenoxy bridges from two ligands.

  14. The effects of sulfur intercalation on the optical properties of artificial 'hackmanite', Na8[Al6Si6O24]Cl1.8S0.1; 'sulfosodalite', Na8[Al6Si6O24]S; and natural tugtupite, Na8

    DEFF Research Database (Denmark)

    Warner, Terence Edwin; Hutzen Andersen, Jan

    2012-01-01

    .8S0.1 destroys the tenebrescence and induces a permanently pale blue and, at higher temperature, a pale green coloration. The effect on Na8[Al6Si6O24]S induced similar colorations but of a deeper hue. Annealing tugtupite, Na8[Be2Al2Si8O24](Cl,S)2-x under a sulfur atmosphere over the range 600-700 °C......, destroyed the tenebrescence and resulted in a colourless tugtupite; but did not effect the photoluminescence. This suggests that the chemical species responsible for the tenebrescence in tugtupite is unlikely to be the same as that for the luminescence....

  15. Structural investigation and microwave characteristics of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Manaf, Azwar [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Indonesia of University (Indonesia); Adi, Wisnu Ari, E-mail: dwisnuaa@batan.go.id [Center for Technology of Nuclear Industry Material, National Nuclear Energy Agency (Indonesia)

    2014-03-24

    Synthesis and characterization of (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} absorbing material by mechanical alloying process has been performed. The absorbing material was prepared by oxide materials, namely BaCO{sub 3}, La{sub 2}O{sub 3}, TiO{sub 2}, Fe{sub 2}O{sub 3}, and MnCO{sub 3}. The mixture was milled for 10 h and then sintered at a temperature of 1000 ° C for 10 h. The refinement results of x-ray diffraction pattern of lanthanum manganite substituted with barium showed that the sample consisted of two phases, namely, La{sub 0.9125}MnO{sub 3} phase which has a structure monoclinic (I12/a1) with lattice parameters a = 5.527(1) Å, b = 5.572(1) Å and c = 7.810(1) Å, α = γ = 90° and β = 89.88(5)°, the unit cell volume of V = 240.57(8) Å{sup 3}, and the atomic density of ρ = 6.238 gr.cm{sup −3}. The microstructure analyses showed that the particle shapes was polygonal with the varied particle sizes of 1 ∼ 3 μm distributed homogeneously on the surface of the samples. The results of the electromagnetic wave absorption curve analysis by using a vector network analyzer (VNA) showed that the sample can absorb microwaves in the frequency range of 8-15 GHz with a very wide absorption bandwidth. It indicates that the as prepared absorber presents potential absorbing property in X and Ku-band. We concluded that the (Ba{sub 0.2}La{sub 0.8})Fe{sub 0.2}Mn{sub 0.4}Ti{sub 0.4}O{sub 3} material can be applied as a candidate absorber material of microwaves or electromagnetic wave.

  16. Effect of chemical treatment on the electrochemical properties of Li1.2NixMn0.8-xO2 (x = 0.2 and 0.25) in lithium-ion batteries

    Science.gov (United States)

    Konishi, Hiroaki; Hirano, Tatsumi; Takamatsu, Daiko; Gunji, Akira; Feng, Xiaoliang; Furutsuki, Sho; Okumura, Takefumi; Terada, Shohei

    2018-02-01

    The effect of chemical treatment using (NH4)2SO4 on the electrochemical properties of Li1.2Ni0.2Mn0.6O2 and Li1.2Ni0.25Mn0.55O2 was investigated. The treatment was effective in improving the Coulombic efficiency and discharge capacity of a Li1.2Ni0.2Mn0.6O2 cathode, but treatment with too much (NH4)2SO4 degraded the cathode's electrochemical performance. The effect of (NH4)2SO4 treatment on the charge-discharge reaction mechanism of Li1.2Ni0.2Mn0.6O2 was investigated by evaluating reaction potential, particle configuration, and oxidation state of transition metal. The experimental results indicated that the changes in the electrochemical performance of the treated cathodes were attributed to the changes in the surface state and of the element contributing to the redox reaction. Treatment with an appropriate amount of (NH4)2SO4 also improved the electrochemical performance of the high-nickel-content lithium-rich layer-structured cathode material Li1.2Ni0.25Mn0.55O2.

  17. Rietveld refinement of the crystal structures of Rb2XSi5O12 (X = Ni, Mn

    Directory of Open Access Journals (Sweden)

    Anthony M. T. Bell

    2016-02-01

    Full Text Available The synthetic leucite silicate framework mineral analogues Rb2XSi5O12 {X = Ni [dirubidium nickel(II pentasilicate] and Mn [dirubidium manganese(II pentasilicate]} have been prepared by high-temperature solid-state synthesis. The results of Rietveld refinements, using X-ray powder diffraction data collected using Cu Kα X-rays, show that the title compounds crystallize in the space group Pbca and adopt the cation-ordered structure of Cs2CdSi5O12 and other leucites. The structures consist of tetrahedral SiO4 and XO4 units sharing corners to form a partially substituted silicate framework. Extraframework Rb+ cations sit in channels in the framework. All atoms occupy the 8c general position for this space group. In these refined structures, silicon and X atoms are ordered onto separate tetrahedrally coordinated sites (T-sites. However, the Ni displacement parameter and the Ni—O bond lengths suggest that for the X = Ni sample, there may actually be some T-site cation disorder.

  18. Luminescent Properties of Sr4Si3O8Cl4:Eu2+, Bi3+ Phosphors for Near UV InGaN-Based Light-Emitting-Diodes

    Directory of Open Access Journals (Sweden)

    Wangqing Shen

    2015-12-01

    Full Text Available Sr4Si3O8Cl4 co-doped with Eu2+, Bi3+ were prepared by the high temperature reaction. The structure and luminescent properties of Sr4Si3O8Cl4:Eu2+, Bi3+ were investigated. With the introduction of Bi3+, luminescent properties of these phosphors have been optimized. Compared with Sr3.90Si3O8Cl4:0.10Eu2+, the blue-green phosphor Sr3.50Si3O8Cl4:0.10Eu2+, 0.40Bi3+ shows stronger blue-green emission with broader excitation in near-UV range. Bright blue-green light from the LED means this phosphor can be observed by the naked eye. Hence, it may have an application in near UV LED chips.

  19. Enhanced electrochemical performance of LiMn2O4 by constructing a stable Mn2+-rich interface

    Science.gov (United States)

    Lu, Zhongpei; Lu, Xiaojun; Ding, Jingjing; Zhou, Ting; Ge, Tao; Yang, Gang; Yin, Fan; Wu, Mingfang

    2017-12-01

    Spinel LiMn2O4 has drawn continuous attentions due to its low cost, good electrochemical performance, environmental friendliness and natural abundant resources. In view of its severe capacity fading, some types of manganese-based compounds with different Mn oxidation states are selected to protect bare LiMn2O4 by constructing a stable coating layer. In this work, LiMn2O4@LiMnPO4 composite, spherical LiMn2O4 (LMO) as core and Mn2+-rich phase of LiMnPO4 (LMP) as shell, is designed and synthesized. Two composites of LiMn2O4 particles coated with 3 wt% and 10 wt% LiMnPO4 have been compared studied. After 100 cycles at 0.5C rate, the two samples deliver capacity retentions of 96.63% and 93.23% of their initial capacities. Moreover, LMO coated by 3 wt% LiMnPO4 delivers 100.3 mAh g-1 after 200 cycles at 10C rate and 76.3 mAh g-1 after 1000 cycles at 20C rate, much higher than bare LiMn2O4 with 90 mAh g-1 and 45.8 mAh g-1, respectively. This core-shell structure with Mn2+-rich phase as a coating layer effectively enhance the material's cycling performance and rate capacity by reducing the contact of LiMn2O4 with electrolyte.

  20. Crystal structures and thermal decomposition of permanganates AE[MnO{sub 4}]{sub 2} . n H{sub 2}O with the heavy alkaline earth elements (AE=Ca, Sr and Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Henning, Harald; Bauchert, Joerg M.; Conrad, Maurice; Schleid, Thomas [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie

    2017-10-01

    Reexamination of the syntheses and crystal structures as well as studies of the thermal decomposition of the heavy alkaline earth metal permanganates Ca[MnO{sub 4}]{sub 2} . 4 H{sub 2}O, Sr[MnO{sub 4}]{sub 2} . 3 H{sub 2}O and Ba[MnO{sub 4}]{sub 2} are the focus of this work. As an alternative to the very inelegant Muthmann method, established for the synthesis of Ba[MnO{sub 4}]{sub 2} a long time ago, we employed a cation-exchange column loaded with Ba{sup 2+} cations and passed through an aqueous potassium-permanganate solution. We later used this alternative also with strontium- and calcium-loaded columns and all the compounds synthesized this way were indistinguishable from the products of the established methods. Ca[MnO{sub 4}]{sub 2} . 4 H{sub 2}O exhibiting [CaO{sub 8}] polyhedra crystallizes in the orthorhombic space group Pccn with the lattice parameters a=1397.15(9), b=554.06(4) and c=1338.97(9) pm with Z=4, whereas Sr[MnO{sub 4}]{sub 2} . 3 H{sub 2}O with [SrO{sub 10}] polyhedra adopts the cubic space group P2{sub 1}3 with a=964.19(7) pm and Z=4. So the harder the AE{sup 2+} cation, the higher its demand for hydration in aqueous solution. Consequently, the crystal structure of Ba[MnO{sub 4}]{sub 2} in the orthorhombic space group Fddd with a=742.36(5), b=1191.23(7) and c=1477.14(9) pm with Z=8 lacks any crystal water, but contains [BaO{sub 12}] polyhedra. During the thermal decomposition of Ca[MnO{sub 4}]{sub 2} . 4 H{sub 2}O, the compound expels up to two water molecules of hydration, before the crystal structure collapses after the loss of the third H{sub 2}O molecule at 157 C. The crystal structure of Sr[MnO{sub 4}]{sub 2} . 3 H{sub 2}O breaks down after the expulsion of the third water molecule as well, but this already occurs at 148 C. For both the calcium and the strontium permanganate samples, orthobixbyite-type α-Mn{sub 2}O{sub 3} and the oxomanganates(III,IV) AEMn{sub 3}O{sub 6} (AE=Ca and Sr) remain as final decomposition products at 800 C

  1. Activation of sp3-CH Bonds in a Mono(pentamethylcyclopentadienyl)yttrium Complex. X-ray Crystal Structures and Dynamic Behavior of Cp*Y(o-C6H4CH2NMe2)2 and Cp*Y[o-C6H4CH2NMe(CH2-μ)][μ-o-C6H4CH2NMe(CH2-μ)]YCp*[THF

    NARCIS (Netherlands)

    Booij, Martin; Kiers, Niklaas H.; Meetsma, Auke; Teuben, Jan H.; Smeets, Wilberth J.J.; Spek, Anthony L.

    1989-01-01

    Reaction of Y(o-C6H4CH2NMe2)3 (1) with Cp*H gives Cp*Y(o-C6H4CH2NMe2)2 (2), which crystallizes in the monoclinic space group P21/n (No. 14) with a = 18.607 (4) Å, b = 15.633 (3) Å, c = 8.861 (3) Å, β = 102.73 (3)°, and Z = 4. Least-squares refinement with 3006 independent reflections (F > 4.0σ(F))

  2. SYNTHESIS AND STRUCTURAL CHARACTERISTICS OF BIS(CITRATEGERMANATES(IV (Hbipy2[Ge(HCit2]•2H2O AND [CuCl(bipy2]2[Ge(HCit2]•8H2O

    Directory of Open Access Journals (Sweden)

    Inna Seifullina

    2016-12-01

    Full Text Available The crystalline compounds (Hbipy2[Ge(HCit22H2O (1 and CuCl(bipy2]2[Ge(HCit28H2O (2 (where H4Cit is citric acid, bipy is 2,2ʹ-bipyridine were obtained for the fi rst time and their structures were determined by the single-crystal X-ray diffraction method. Compounds were characterized by IR spectroscopy, thermogravimetric (TGA and elemental analyses. Both compounds are formed with complex bis(citrategermanate anion and protonated 2,2’-bipyridine or [Cu(bipy2Cl]+ as cations in compounds 1 and 2, respectively.

  3. Synthesis and complex study of the crystal hydrate Zn{sub 2}ZrF{sub 8}.12H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Voit, Elena; Didenko, Nina; Gayvoronskaya, Kseniya; Slobodyuk, Arseniy; Gerasimenko, Andrey [Institute of Chemistry, Far-Eastern Branch, Russian Academy of Sciences, 159 Prosp. 100-Letiya Vladivostoka, 690022 Vladivostok (Russian Federation)

    2016-05-15

    The synthesis and study of structure and properties of a crystal hydrate of the composition Zn{sub 2}ZrF{sub 8}.12H{sub 2}O were performed by XRD, DTA analysis as well as IR, Raman, and {sup 1}H, and {sup 19}F NMR, including {sup 19}F MAS NMR spectroscopy. The compound crystallizes in the monoclinic syngony with the following unit cell parameters: a = 20.9649 (12), b = 9.6851 (6), c = 24.0209 (14) Aa, β = 103.742 (2) , space group C2/c, Z = 12. The structure is built from monomeric complex [ZrF{sub 8}]{sup 4-} and [Zn(H{sub 2}O){sub 6}]{sup 2+} linked through hydrogen bonds of different lengths (O-H..F and O-H..O). The peculiarity of the structure consists in the presence of short hydrogen bonds (interatomic O..F distances 2.5-2.6 Aa). Analysis of the IR and Raman spectra allowed interpretation of bands corresponding to vibrations of the [ZrF{sub 8}]{sup 4-} anion and to describe hydrogen bonds in the structure of Zn{sub 2}ZrF{sub 8}.12H{sub 2}O. Phase transformations in the process of thermal dehydration were studied on the basis of changes in vibrational and NMR spectra. It has been established that the interligand exchange in the complex anion takes place as early as at -103 C, whereas no reorientation of hexaaquacations was observed up to 47 C. At 58 C, the compound undergoes an incongruent melting accompanied with formation of much more stable ZnZrF{sub 6}.6H{sub 2}O and an aqueous salty liquid phase characterized with high mobility of fluorine atoms and protons, in accordance with the NMR spectroscopic data. (Copyright copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Chemical effects of (n, γ) nuclear reaction on (Mo6Cl8)Cl4

    International Nuclear Information System (INIS)

    Fucugauchi, L.A.; Millan, S.; Mondragon, A.; Solache-Rios, M.

    1994-01-01

    The chemical effects of 98 Mo(n, γ) 99 Mo reaction on molybdenum(II) chloride [(Mo 6 Cl 8 )Cl 4 ] have been studied. Retention, thermal and radiolytical annealing were determined. It was found that this molybdenum compound has low retention, a negligible tendency to thermal annealing and a virtual insensitivity to hydrolysis. For practical applications in the enrichment of 99 Mo by the Shilard-Chalmers method, molybdenum(II) chloride [(Mo 6 Cl 8 )Cl 4 ] appears to offer good prospects. (author) 14 refs.; 2 figs

  5. Tb3O2Cl[SeO3]2 and Tb5O4Cl3[SeO3]2: Oxide Chloride Oxoselenates(IV) of Trivalent Terbium with ''Lone-Pair'' Channel or Layer Structures

    International Nuclear Information System (INIS)

    Wontcheu, Joseph; Schleid, Thomas

    2005-01-01

    Orthorhombic Tb 3 O 2 Cl[SeO 3 ] 2 (Pnma; a = 535.16(4), b = 1530.51(9), c = 1081.72(7) pm; Z = 4) is formed by reacting a stoichiometric mixture of Tb 4 O 7 , Tb, TbCl 3 , and SeO 2 in a suitable molar ratio (12: 8: 7: 42) within seven days in an evacuated sealed silica tube at 850 C. The needle-shaped, colourless single crystals (light, water and air stable) exhibit one-dimensional strands [(Tb1) 3/3 (Tb2) 2/1 O 4/2 ] 5+ [O 2 Tb 3 ] 5+ along [100] formed by two parallel chains [OTb 4/2 ] 4+ of trans-edge connected [OTb 4 ] 10+ tetrahedra (d(O-Tb) = 220 - 231 pm) which share an extra edge per chain link. The crystal structure contains two crystallographically different Tb 3+ cations: Tb1 is coordinated as bicapped trigonal prism, while Tb2 resides in square antiprismatic coordination. The Se 4+ coordination is best described as Ψ 1 tetrahedral ([SeO 3 E] 2- ; E: non-binding electron pair). The non-binding ''lone-pair'' electrons of four [SeO 3 ] 2- groups and two Cl - anions form pseudo-hexagonal empty channels along [100] between four cationic double chains. Tb 5 O 4 Cl 3 [SeO 3 ] 2 was prepared likewise as plate-like, colourless single crystals by solid-state reaction of an admixture of Tb 4 O 7 , Tb, TbOCl, TbCl 3 , and SeO 2 (molar ratio: 9: 6: 21: 7: 28) in an evacuated sealed silica tube during seven days at 850 C. This compound crystallizes in the monoclinic system (C2/m; a = 1229.13(9), b = 546.17(4), c = 978.79(7) pm, β = 90.485(6) ; Z = 2) and contains three crystallographically different Tb 3+ cations in seven- and eightfold coordination of O 2- and Cl - anions, respectively. The crystal structure of Tb 5 O 4 Cl 3 [SeO 3 ] 2 is layered and built up of corrugated terbium-oxygen sheets [O 4 Tb 5 ] 7+ formed by edge- and vertex-shared [OTb 4 ] 10+ tetrahedra (d(O-Tb) = 226-232 pm) spreading parallel (001). The structure is strongly related to the ''lone-pair'' channel structures of Tb 2 O[SeO 3 ] 2 and Tb 3 O 2 Cl[SeO 3 ] 2 , where single ([OTb 2 ] 4

  6. Preparation, Characterization, and Structure of Two Layered Molybdenum(VI) Phosphates: KMo(H 2O)O 2PO 4 and NH 4Mo(H 2O)O 2PO 4

    Science.gov (United States)

    Millini, Roberto; Carati, Angela

    1995-08-01

    New layered Mo(VI) compounds, KMo(H 2O)O 2PO 4 (I) and NH 4Mo(H 2O)O 2PO 4 (II), were synthesized hydrothermally and their structures were determined from single-crystal X-ray analysis. Compounds (I) and (II) are isostructural and crystallize in the monoclinic P2 1/ n space group with a = 12.353(3), b = 8.623(2), c = 5.841(1) Å, β = 102.78(1)°, V = 606.8(2) Å 3, Z = 4, and R = 0.027 ( Rw = 0.030) for compound (I) and a = 12.435(3), b = 8.761(2), c = 6.015(1), β = 103.45(1)°, V = 637.3(2) Å 3, Z = 4, and R = 0.040 ( Rw = 0.041) for compound (II). The structure consists of layers built up of eight- and four-membered rings resulting from the alternation of corner-sharing [MoO 6] octahedra and [PO 4] tetrahedra. The layers stack along the (1¯01) direction by intercalating K and NH 4 ions.

  7. Synthesis, Structure and Properties of Various Molecules Based on the 4,8,12-trioxa-4,8,12,12c-tetrahydrodibenzo[cd,mn]pyrene System With an Evaluation of the Effect Differing Molecular Substitution Patterns Has on the Space Group Symmetry

    DEFF Research Database (Denmark)

    Faldt, André; Krebs, Frederik C; Thorup, Niels

    1997-01-01

    of opposite chirality are present within the unit cell, Finally compound 13 crystallises in a centrosymmetric space group. The room temperature pyroelectric coefficient of 3 has been determined, The spatial extent of the trioxatriangulene ground system has been perturbed by chemical substitution......4,8,12-Trioxa-4,8,12,12c-tetrahydrodibenzo [cd,mn]pyrene (3),2,6,10-tri-tert-butyl-4,8,12 -trioxa-4,8,12,12c-tetrahydrodibenzo [cd,mn]pyrene (11) and 2,6,10-tri-tert-butyl-4,8,12-trioxa-12c -methyl-4,8,12,12c -tetrahydrodibenzo[cd,mn]pyrene (12)have been synthesised and their crystal structures...... and the effect: of the substitutions upon the space group symmetry of the chemical derivative has been uncovered by X-ray structural resolution, The non-centrosymmetric point group symmetry of the molecules is reflected in a non-centrosymmetric space group symmetry whenever the spatial perturbations do...

  8. Synthesis and characterization of La1+xSr2-xCoMnO7-δ (x=0,0.2; δ=0,1)

    International Nuclear Information System (INIS)

    El Shinawi, H.; Bertha, A.; Hadermann, J.; Herranz, T.; Santos, B.; Marco, J.F.; Berry, F.J.; Greaves, C.

    2010-01-01

    The n=2 Ruddlesden-Popper phases LaSr 2 CoMnO 7 and La 1.2 Sr 1.8 CoMnO 7 have been synthesized by a sol-gel method. The O6-type phases LaSr 2 CoMnO 6 and La 1.2 Sr 1.8 CoMnO 6 were produced by reduction of the O7 phases under a hydrogen atmosphere. The materials crystallize in the tetragonal I4/mmm space group with no evidence of long-range cation order in the neutron and electron diffraction data. Oxygen vacancies in the reduced materials are located primarily at the common apex of the double perovskite layers giving rise to square pyramidal coordination around cobalt and manganese ions. The oxidation states Co 3+ /Mn 4+ and Co 2+ /Mn 3+ predominate in the as-prepared and reduced materials, respectively. The materials are spin glasses at low temperature and the dominant magnetic interactions change from ferro- to antiferromagnetic following reduction. - Graphical abstract: The n=2 Ruddlesden-Popper phases LaSr 2 CoMnO 7 , La 1.2 Sr 1.8 CoMnO 7 , LaSr 2 CoMnO 6 and La 1.2 Sr 1.8 CoMnO 6 are synthesized and characterized.

  9. (E-2-[2-(4-Carboxyphenylethenyl]-8-hydroxyquinolin-1-ium chloride ethanol monosolvate

    Directory of Open Access Journals (Sweden)

    Edwin Weber

    2013-12-01

    Full Text Available In the title compound, C18H14NO3+·Cl−·CH3CH2OH, the dihedral angle formed by the mean planes of the quinolinium and benzene rings is 3.4 (1°, while the carboxy substituent is tilted at an angle of 4.8 (1° with respect to the benzene ring. There is a short N—H...O contact in the cation. In the crystal, due to the planar molecular geometry, two-dimensional aggregates are formed parallel to (221 via C—H...O, C—H...Cl, O—H...Cl and N—H...Cl hydrogen bonds. Interlayer association is accomplished by O—Hethanol...Cl and O—H...Oethanol hydrogen bonds and π–π stacking interactions [centroid–centroid distances vary from 3.6477 (12 to 3.8381 (11 Å]. A supramolecular three-dimensional architecture results from a stacked arrangement of layers comprising the ionic and hydrogen-bonded components.

  10. Oxothiomolybdenum derivatives of the superlacunary crown heteropolyanion {P8W48}: structure of [K4{Mo4O4S4(H2O)3(OH)2}2(WO2)(P8W48O184)]30– and studies in solution.

    Science.gov (United States)

    Korenev, Vladimir S; Floquet, Sébastien; Marrot, Jérôme; Haouas, Mohamed; Mbomekallé, Israël-Martyr; Taulelle, Francis; Sokolov, Maxim N; Fedin, Vladimir P; Cadot, Emmanuel

    2012-02-20

    Reaction of the cyclic lacunary [H(7)P(8)W(48)O(184)](33-) anion (noted P(8)W(48)) with the [Mo(2)S(2)O(2)(H(2)O)(6)](2+) oxothiocation led to two compounds, namely, [K(4){Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(WO(2))(P(8)W(48)O(184))](30-) (denoted 1) and [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(P(8)W(48)O(184))](36-) (denoted 2), which were characterized in the solid state and solution. In the solid state, the structure of [K(4){Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(WO(2))(P(8)W(48)O(184))](30-) reveals the presence of two disordered {Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2+) "handles" connected on both sides of the P(8)W(48) ring. Such a disorder is consistent with the presence of two geometrical isomers where the relative disposition of the two {Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2+) handles are arranged in a perpendicular or parallel mode. Such an interpretation is fully supported by (31)P and (183)W NMR solution studies. The relative stability of both geometrical isomers appears to be dependent upon the nature of the internal alkali cations, i.e., Na(+) vs K(+), and increased lability of the two {Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2+) handles, compared to the oxo analogous, was clearly identified by significant broadening of the (31)P and (183)W NMR lines. Solution studies carried out by UV-vis spectroscopy showed that formation of the adduct [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(P(8)W(48)O(184))](36-) occurs in the 1.5-4.7 pH range and corresponds to a fast and quantitative condensation process. Furthermore, (31)P NMR titrations in solution reveal formation of the "monohandle" derivative [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(P(8)W(48)O(184))](38-) as an intermediate prior to formation of the "bishandle" derivatives. Furthermore, the electrochemical behavior of [{Mo(4)O(4)S(4)(H(2)O)(3)(OH)(2)}(2)(P(8)W(48)O(184))](36-) was studied in aqueous medium and compared with the parent anion P(8)W(48).

  11. Design and syntheses of hybrid metal-organic materials based on K3[M(C2O4)3]·3H2O [M(III)=Fe, Al, Cr] metallotectons

    Science.gov (United States)

    Sun, Yayong; Zong, Yingxia; Ma, Haoran; Zhang, Ao; Liu, Kang; Wang, Debao; Wang, Wenqiang; Wang, Lei

    2016-05-01

    By using K3[M(C2O4)3]·3H2O [M(III)=Fe, Al, Cr] (C2O42-=oxalate) metallotectons as the starting material, we have synthesized eight novel complexes with formulas [{Fe(C2O4)2(H2O)2}2]·(H-L1)2·H2O 1, [Fe(C2O4)Cl2]·(H2-L2)0.5·(L2)0.5·H2O 2, [{Fe(C2O4)1.5Cl2}2]·(H-L3)43, [Fe2(C2O4)Cl8]·(H2-L4)2·2H2O 4, K[Al(C2O4)3]·(H2-L5)·2H2O 5, K[Al(C2O4)3]·(H-L6)2·2H2O 6, K[Cr(C2O4)3]·2H2O 7, Na[Fe(C2O4)3]·(H-L6)2·2H2O 8 (with L1=4-dimethylaminopyridine, L2=2,3,5,6-tetramethylpyrazine, L3=2-aminobenzimidazole, L4=1,4-bis-(1H-imidazol-1-yl)benzene, L5=1,4-bis((2-methylimidazol-1-yl)methyl)benzene, L6=2-methylbenzimidazole). Their structures have been determined by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra and thermogravimetric analyses. Compound 3 is a 2D H-bonded supramolecular architecture. Others are 3D supramolecular structures. Compound 1 shows a [Fe(C2O4)2(H2O)2]- unit and 3D antionic H-bonded framework. Compound 2 features a [Fe(C2O4)Cl2]- anion and 1D iron-oxalate-iron chain. Compound 3 features a [Fe2(C2O4)3Cl4]4- unit. Compound 4 features distinct [Fe2(C2O4)Cl8]4- units, which are mutual linked by water molecules to generated a 2D H-bonded network. Compound 5 features infinite ladder-like chains constructed by [Al(C2O4)3]3- units and K+ cations. The 1D chains are further extended into 3D antionic H-bonded framework through O-H···O H-bonds. Compounds 6-8 show 2D [KAl(C2O4)3]2- layer, [KCr(C2O4)3]2- layer and [NaFe(C2O4)3]2- layer, respectively.

  12. Octa­akis(4-amino­pyridine)-1κ4 N 1,2κ4 N 1-aqua-2κO-μ-carbonato-1:2κ3 O,O′:O′′-dinickel(II) dichloride penta­hydrate

    Science.gov (United States)

    Fun, Hoong-Kun; Sinthiya, A; Jebas, Samuel Robinson; Ravindran Durai Nayagam, B.; Alfred Cecil Raj, S.

    2008-01-01

    In the title compound, [Ni2(CO3)(C5H6N2)8(H2O)]Cl2·5H2O, one of the the NiII ions is six-coordinated in a distorted octa­hedral geometry, with the equatorial plane defined by four pyridine N atoms from four amino­pyridine ligands, the axial positions being occupied by one water O and a carbonate O atom. The other NiII ion is also six-coordinated, by four other pyridine N atoms from four other amino­pyridine ligands and two carbonate O atoms to complete a distorted octa­hedral geometry. In the crystal structure, mol­ecules are linked into an infinite three-dimensional network by O—H⋯O, N—H⋯Cl, N—H⋯O, O—H⋯N, C—H⋯O, C—H⋯N and C/N—H⋯π inter­actions involving the pyridine rings. PMID:21580879

  13. Proton-transfer compounds of 8-hydroxy-7-iodoquinoline-5-sulfonic acid (ferron) with 4-chloroaniline and 4-bromoaniline.

    Science.gov (United States)

    Smith, Graham; Wermuth, Urs D; Healy, Peter C

    2007-07-01

    The crystal structures of the proton-transfer compounds of ferron (8-hydroxy-7-iodoquinoline-5-sulfonic acid) with 4-chloroaniline and 4-bromoaniline, namely 4-chloroanilinium 8-hydroxy-7-iodoquinoline-5-sulfonate monohydrate, C(6)H(7)ClN(+) x C(9)H(5)INO(4)S(-) x H(2)O, and 4-bromoanilinium 8-hydroxy-7-iodoquinoline-5-sulfonate monohydrate, C(6)H(7)BrN(+) x C(9)H(5)INO(4)S(-) x H(2)O, have been determined. The compounds are isomorphous and comprise sheets of hydrogen-bonded cations, anions and water molecules which are extended into a three-dimensional framework structure through centrosymmetric R(2)(2)(10) O-H...N hydrogen-bonded ferron dimer interactions.

  14. Microstructure, crystal structure and electrical properties of Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} ceramics obtained at different sintering conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bodak, O.; Akselrud, L.; Demchenko, P.; Kotur, B.; Mrooz, O.; Hadzaman, I.; Shpotyuk, O.; Aldinger, F.; Seifert, H.; Volkov, S.; Pekhnyo, V

    2002-12-16

    Details of the formation of Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} ceramics under different sintering conditions have been studied by optical microscopy, scanning electron microscopy (SEM), electron probe and energy dispersive spectroscopy (EDX) microanalyses, X-ray diffraction (XRD) and electrical resistivity measurements. Microstructure studies of samples sintered at 1170 deg. C for 1 h indicated the presence of a secondary phase besides the main spinel phase with modified composition. XRD measurements showed that the spinel phase exhibits a tetragonally distorted spinel structure (space group I4{sub 1}/amd, a=5.9410(5) A, c=8.4196(15) A). The secondary phase (solid solution based on NiO) crystallizes with the NaCl-type structure (space group Fm3-bar m, a=4.1872(3) A). The content of the secondary phase in ceramics is 10.61 mass%. For NiMn{sub 2}O{sub 4} ceramics, prepared under the same sintering conditions, the decomposition with Ni{sub 1-x}Mn{sub x}O solid solution (NaCl-type structure) and spinel phase formation have been observed. The tetragonal modification of the spinel phase for NiMn{sub 2}O{sub 4} ceramics is more preferable (space group I4{sub 1}/amd, a=5.9764(5) A, c=8.4201(8) A). The distribution of atoms in the structure has been proposed for both ceramics. According to XRD results the Cu{sub 0.1}Ni{sub 0.8}Co{sub 0.2}Mn{sub 1.9}O{sub 4} ceramic samples, sintered at 920 deg. C for 8 h (program 1), at 920 deg. C for 8 h and at 750 deg. C for 24 h (program 2), at 920 deg. C for 8 h, at 1200 deg. C for 1 h and at 920 deg. C for 24 h (program 3) and at 920 deg. C for 8 h, at 1200 deg. C for 1 h, at 920 deg. C for 24 h and at 750 deg. C for 48 h (program 4), contain a single phase with the cubic spinel structure (space group Fd3-bar m). Small residuals of the secondary phase for the ceramics, prepared via programs 3 and 4, have been observed by SEM investigations. The structure transformations of the spinel phase for Cu{sub 0.1}Ni{sub 0.8}Co

  15. Magnetic and ultrasonic studies on double layered CMR manganite La1.2Sr1.8Mn2O7

    International Nuclear Information System (INIS)

    Reddy, Y.S.; Vishnuvardhan Reddy, C.

    2014-01-01

    Magnetic and ultrasonic studies were done on La 1.2 Sr 1.8 Mn 2 O 7 to understand the correlation between its magnetic and ultrasonic transitions. The sample transforms from paramagnetic-insulator to ferromagnetic-metallic state at T c ≈124 K. The significant hardening in longitudinal sound velocity measurements (below T c ) is attributed to the coupling between ferromagnetic spins and longitudinal acoustic phonons. (author)

  16. Oxidation of iodide and iodine on birnessite (delta-MnO2) in the pH range 4-8.

    Science.gov (United States)

    Allard, Sébastien; von Gunten, Urs; Sahli, Elisabeth; Nicolau, Rudy; Gallard, Hervé

    2009-08-01

    The oxidation of iodide by synthetic birnessite (delta-MnO(2)) was studied in perchlorate media in the pH range 4-8. Iodine (I(2)) was detected as an oxidation product that was subsequently further oxidized to iodate (IO(3)(-)). The third order rate constants, second order on iodide and first order on manganese oxide, determined by extraction of iodine in benzene decreased with increasing pH (6.3-7.5) from 1790 to 3.1M(-2) s(-1). Both iodine and iodate were found to adsorb significantly on birnessite with an adsorption capacity of 12.7 microM/g for iodate at pH 5.7. The rate of iodine oxidation by birnessite decreased with increasing ionic strength, which resulted in a lower rate of iodate formation. The production of iodine in iodide-containing waters in contact with manganese oxides may result in the formation of undesired iodinated organic compounds (taste and odor, toxicity) in natural and technical systems. The probability of the formation of such compounds is highest in the pH range 5-7.5. For pH iodine is quickly oxidized to iodate, a non-toxic and stable sink for iodine. At pH >7.5, iodide is not oxidized to a significant extent.

  17. catena-Poly[[[triaqua[3-(4-carboxyphenoxyphthalato-κO2]manganese(II]-μ-4,4′-bipyridine-κ2N:N′] 4,4′-bipyridine monosolvate dihydrate

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2013-02-01

    Full Text Available In the title compound, {[Mn(C15H8O7(C10H8N2(H2O3]·C10H8N2·2H2O}n, the bridging mode of the coordinating 4,4′-bipyridine ligands leads to the formation of polymeric zigzag chains parallel to [0-11]. The chains are separated by 4,4′-bipyridine and water solvent molecules. Within a chain, the MnII atom is six-coordinated by two N atoms of the bridging 4,4′-bipyridine ligands, three water O atoms and one carboxylate O atom of a single deprotonated 3-(4-carboxyphenoxyphthalic acid ligand. Both coordinating and solvent 4,4′-bipyridine molecules are situated on centres of inversion. An intricate network of O—H...O and O—H...N hydrogen bonds involving the carboxy group, the coordinating water molecules and the two types of solvent molecules leads to the formation of a three-dimensional network.

  18. White LED based on CaAl2Si2O8:Eu2+ Mn2+ phosphor and CdS/ZnS quantum dots

    Science.gov (United States)

    Shen, Changyu; Zhong, Chuan; Hou, Qianglong; Li, Ke

    2011-02-01

    Core/shell CdS/ZnS quantum dots (QDs) with the emission wavelength of 610nm, was synthesized by thermal deposition using cadmium oxide and selenium as precursors in a hot lauric acid and hexadecylamine trioctylphosphine oxide hybrid. CaAl2Si2O8:Eu2+ Mn2+ phosphor was synthesized by high-temperature solid state reaction at 1290 °C for 2 hours under the H2 reducing atmosphere, and X-ray powder diffraction analysis confirmed the formation of it. It has two emission bands peaking at 420 nm and 580nm originated from the transition 5d to 4f of Eu2+ and 4T1-6A1 of Mn2+, respectively. Blends of CaAl2Si2O8:Eu2+,Mn2+ phosphor and CdS/ZnS QDs exhibited the prominent spectral evolution with an increasing content of QDs. A hybrid white LED, which combines a blue LED with the blend of CaAl2Si2O8:Eu2+ Mn2+ phosphor and QDs with a weight ratio of 2:1, with the CIE coordinate of (0.3183, 0.3036) and CRI of 85 was obtained.

  19. Detailed single crystal EPR lineshape measurements for the single molecule magnets Fe8Br and Mn12-ac

    OpenAIRE

    Hill, S.; Maccagnano, S.; Park, K.; Achey, R. M.; North, J. M.; Dalal, N. S.

    2001-01-01

    It is shown that our multi-high-frequency (40-200 GHz) resonant cavity technique yields distortion-free high field EPR spectra for single crystal samples of the uniaxial and biaxial spin S = 10 single molecule magnets (SMMs) [Mn12O12(CH3COO)16(H2O)4].2CH3COOH.4H2O and [Fe8O2(OH)12(tacn)6]Br8.9H2O. The observed lineshapes exhibit a pronounced dependence on temperature, magnetic field, and the spin quantum numbers (Ms values) associated with the levels involved in the transitions. Measurements ...

  20. Thermodynamic characterization of Ni3TeO6, Ni2Te3O8 and NiTe2O5

    Science.gov (United States)

    Dawar, Rimpi; Babu, R.; Ananthasivan, K.; Anthonysamy, S.

    2017-09-01

    Measurement of vapour pressure of TeO2(g) over the biphasic mixture Ni3TeO6 (s) + NiO(s) in the temperature range 1143-1272 K was carried out using transpiration-thermogravimetric technique (TTG). Gibbs energy of formation of Ni3TeO6 was obtained from the temperature dependence of vapour pressure of TeO2 (g) generated by the incongruent vapourisation reaction, Ni3TeO6 (s) → NiO(s) + TeO2 (g) + 1/2 O2 in the temperature range 1143-1272 K. An isoperibol type drop calorimeter was used to measure the enthalpy increments of Ni3TeO6, Ni2Te3O8 and NiTe2O5. Thermodynamic functions viz., heat capacity, entropy and Gibbs energy functions of these compounds were derived from the experimentally measured enthalpy increment values. Third-law analysis was carried out to ascertain absence of temperature dependent systematic errors in the measurement of vapour pressure of TeO2 (g). A value of -1265.1 ± 1.5 kJ mol-1 was obtained for Δ Hf,298K o (Ni3TeO6) using third-law analysis.

  1. Intermolecular C-H···O, Cl···Cl and π-π interactions in the 2-dichloromethyl derivative of vitamin K3.

    Science.gov (United States)

    Soave, Raffaella; Colombo, Pietro

    2013-12-15

    The title 1,4-naphthoquinone, 2-dichloromethyl-3-methyl-1,4-dihydronaphthalene-1,4-dione, C12H8Cl2O2, is a chlorinated derivative of vitamin K3, which is a synthetic compound also known as menadione. Molecules of (I) are planar and lie on a crystallographic mirror plane (Z' = 0.5) in the space group Pnma. They are connected to each other by C-H···O hydrogen bonds, forming two-dimensional layers parallel to the ac plane. In addition, Cl···Cl and π-π interactions link adjacent molecules in different layers, thus forming zigzag ribbons along the b axis, such that a three-dimensional architecture is generated.

  2. (2,3,7,8,12,13,17,18-Octaethylporphyrinato-κ4Ncobalt(II–2-nitrobenzaldehyde (1/2

    Directory of Open Access Journals (Sweden)

    Anissa Mansour

    2012-09-01

    Full Text Available The asymmetric unit of the title compound, [Co(C36H44N42C7H5NO3, is composed of one half of the complex, arranged about an inversion center, and a complete 2-nitrobenzaldehyde (NBA molecule. The structure consists of columns that contain interleaved molecules of NBA and [CoII(OEP] (OEP is 2,3,7,8,12,13,17,18-octaethylporphyrin, which are stacked along the a axis. The CoII atom is involved in a π interaction with the ring of the NBA molecule with a centroid–metal distance of 3.508 (6 Å. There is an intramolecular C—H...O hydrogen bond in the NBA molecule.

  3. 9-(3-Bromo-5-chloro-2-hydroxyphenyl-10-(2-hydroxyethyl-3,6-diphenyl-3,4,9,10-tetrahydroacridine-1,8(2H,5H-dione

    Directory of Open Access Journals (Sweden)

    Mehmet Akkurt

    2014-06-01

    Full Text Available In the title compound, C33H27BrClNO4, the dihydropyridine ring adopts a flattened boat conformation. The molecular conformation is stabilized by an intramolecular O—H...O hydrogen bond, with an S(8 ring motif. In the crystal, O—H...O, C—H...O and C—H...Cl hydrogen bonds, and C—H...π interactions link the molecules, forming a three-dimensional network. In the acridinedione ring system, the two ring C atoms at the 2- and 3-positions, and the C atom at the 6-position and the atoms of the phenyl ring attached to the C atom at the 6-position are disordered over two sets of sites with occupancy ratios of 0.783 (5:0.217 (5 and 0.526 (18:0.474 (18, respectively.

  4. Crystal structure of N,N′-bis[2-((benzyl{[5-(dimethylaminonaphthalen-1-yl]sulfonyl}aminoethyl]naphthalene-1,8:4,5-tetracarboximide 1,2-dichlorobenzene trisolvate

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Claudio-Catalán

    2016-10-01

    Full Text Available The asymmetric unit of the title compound, C56H50N6O8S2·3C6H4Cl2, contains two half-molecules of the parent, A and B, which both have crystallographic inversion symmetry, together with three 2,3-dichlorobenzene molecules of solvation. Molecules A and B are conformationally similar, with dihedral angles between the central naphthalenediimide ring and the peripheral naphthalene and benzyl rings of 2.43 (7, 81.87 (7° (A and 3.95 (7, 84.88 (7° (B, respectively. The conformations are stabilized by the presence of intramolecular π–π interactions between the naphthalene ring and the six-membered diimide ring of the central naphthalenediimide moiety, with ring centroid-to-centroid distances of 3.5795 (8 Å (A and 3.5640 (8 Å (B. In the crystal, C—H...O hydrogen bonds link the molecules into infinite supramolecular chains along the c axis. These chains are interconnected through C—H...π and offset π–π interactions, generating supramolecular nanotubes which are filled by 1,2-dichlorobenzene molecules.

  5. Neutron investigation of Ru-doped Nd1/2Ca1/2MnO3. Comparison with Cr-doped Nd1/2Ca1/2MnO3

    International Nuclear Information System (INIS)

    Moritomo, Yutaka; Nonobe, Toshihiko; Machida, Akihiko; Ohoyama, Kenji

    2002-01-01

    Lattice and magnetic properties are investigated for 3% Ru- and Cr-doped Nd 1/2 Ca 1/2 MnO 3 . The parent Nd 1/2 Ca 1/2 MnO 3 is a charge-ordered insulator (T CO =250K). With decreasing temperature below ≅210K, these compounds are separated into two perovskite phases, that is, the long-c and short-c phases. The long-c region shows a ferromagnetic transition at T C ≅210K for the Ru-doped compound and ≅130K for the Cr-doped compound, while the short-c region shows antiferromagnetic transition at T N ≅150K for Ru and ≅110K for Cr. We discuss the origin of the enhanced T C for the Ru-doped compound in terms of the effective one-electron bandwidth W of the e g -band. (author)

  6. Evaluation of Ca3(Co,M2O6 (M=Co, Fe, Mn, Ni as new cathode materials for solid-oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Fushao Li

    2015-10-01

    Full Text Available Series compounds Ca3(Co0.9M0.12O6 (M=Co, Fe, Mn, Ni with hexagonal crystal structure were prepared by sol–gel route as the cathode materials for solid oxide fuel cells (SOFCs. Effects of the varied atomic compositions on the structure, electrical conductivity, thermal expansion and electrochemical performance were systematically evaluated. Experimental results showed that the lattice parameters of Ca3(Co0.9Fe0.12O6 and Ca3(Co0.9Mn0.12O6 were both expanded to certain degree. Electron-doping and hole-doping effects were expected in Ca3(Co0.9Mn0.12O6 and Ca3(Co0.9Ni0.12O6 respectively according to the chemical states of constituent elements and thermal-activated behavior of electrical conductivity. Thermal expansion coefficients (TEC of Ca3(Co0.9M0.12O6 were measured to be distributed around 16×10−6 K−1, and compositional elements of Fe, Mn, and Ni were especially beneficial for alleviation of the thermal expansion problem of cathode materials. By using Ca3(Co0.9M0.12O6 as the cathodes operated at 800 °C, the interfacial area-specific resistance varied in the order of M=CoMn, and the over-potential increased in the order of M=Fe≈M=CoMncompounds, Ca3(Co0.9Fe0.12O6 showed the best electrochemical performance and the power density as high as ca. 500 mW cm−2 at 800 °C achieved in the single cell with La0.8Sr0.2Ga0.83Mg0.17O2.815 as electrolyte and Ni–Ce0.8Sm0.2O1.9 as anode. Ca3(Co0.9M0.12O6 (M=Co, Fe, Mn, Ni can be used as the cost-effective cathode materials for SOFCs.

  7. Molecular magnetism of M6 hexagon ring in D(3d) symmetric [(MCl)6(XW9O33)2](12-) (M = Cu(II) and Mn(II), X = Sb(III) and As(III)).

    Science.gov (United States)

    Yamase, Toshihiro; Ishikawa, Hirofumi; Abe, Hiroko; Fukaya, Keisuke; Nojiri, Hiroyuki; Takeuchi, Hideo

    2012-04-16

    Ferromagnetic [n-BuNH(3)](12)[(CuCl)(6)(SbW(9)O(33))(2)]·6H(2)O (1) and antiferromagnetic [n-BuNH(3)](12)[(MnCl)(6)(AsW(9)O(33))(2)]·6H(2)O (4) have been synthesized and structurally and magnetically characterized. Two complexes are structural analogues of [n-BuNH(3)](12)[(CuCl)(6)(AsW(9)O(33))(2)]·6H(2)O (2) and [n-BuNH(3)](12)[(MnCl)(6)(SbW(9)O(33))(2)]·6H(2)O (3) with their ferromagnetic interactions, first reported by us in 2006. (1) When variable temperature (T) direct current (dc) magnetic susceptibility (χ(M)) data are analyzed with the isotropic exchange Hamiltonian for the magnetic exchange interactions, χ(M)T vs T curves fitted by a full matrix diagonalization (for 1) and by the Kambe vector coupling method/Van Vleck's approximation (for 4) yield J = +29.5 and -0.09 cm(-1) and g = 2.3 and 1.9, respectively. These J values were significantly distinguished from +61.0 and +0.14 cm(-1) for 2 and 3, respectively. The magnetization under the pulsed field (up to 10(3) T/s) at 0.5 K exhibits hysteresis loops in the adiabatic process, and the differential magnetization (dM/dB) plots against the pulsed field display peaks characteristic of resonant quantum tunneling of magnetization (QTM) at Zeeman crossed fields, indicating single-molecule magnets for 1-3. High-frequency ESR (HFESR) spectroscopy on polycrystalline samples provides g(∥) = 2.30, g(⊥) = 2.19, and D = -0.147 cm(-1) for 1 (S = 3 ground state), g(∥) = 2.29, g(⊥) = 2.20, and D = -0.145 cm(-1) for 2 (S = 3), and g(∥) = 2.03 and D = -0.007 cm(-1) for 3 (S = 15). An attempt to rationalize the magnetostructural correlation among 1-4, the structurally and magnetically modified D(3d)-symmetric M (=Cu(II) and Mn(II))(6) hexagons sandwiched by two diamagnetic α-B-[XW(9)O(33)](9-) (X = Sb(III) and As(III)) ligands through M-(μ(3)-O)-W linkages, is made. The strongest ferromagnetic coupling for the Cu(6) hexagon of 2, the structure of which approximately provides the Cu(6)(μ(3)-O)(12

  8. Low-temperature heat capacity and thermodynamic properties of [Re{sub 2}(Ile){sub 4}(H{sub 2}O){sub 8}](ClO{sub 4}){sub 6} (Re=Nd, Er, Ile=isoleucine)

    Energy Technology Data Exchange (ETDEWEB)

    Lan Xiaozheng; Tan Zhicheng; Liu Beiping; Nan Zhaodong; Sun Lixian; Xu Fen

    2003-06-03

    The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re{sub 2}(Ile){sub 4}(H{sub 2}O){sub 8}](ClO{sub 4}){sub 6} (where Re=Nd, Er, and Ile=isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature range from 80 to 370 K. Two solid-solid phase transitions were found from the C{sub p} curve of Nd formed complex in the range of 165-175 K with a peak temperature of 167.88 K and in the range of 195-210 K with a peak temperature of 202.13 K. The corresponding molar enthalpies of these phase transitions were determined to be 404.61 J mol{sup -1} and 2.955 kJ mol{sup -1}, respectively. One solid-solid phase transition was found for the Er formed complex in the range of 190-205 K with a peak temperature of 193.42 K. The corresponding molar enthalpy of this transition was 14.11 kJ mol{sup -1}. Smooth heat capacities and thermodynamic functions relative to the standard state (298.15 K), H{sub T}-H{sub 298.15}, S{sub T}-S{sub 298.15} and -[G{sub T}-G{sub 298.15}], of the two compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositions for the pair of compounds were suggested according to the thermogravimetric (TG) analysis.

  9. Cationic Intermixing and Reactivity at the La2 Mo2 O9 /La0.8 Sr0.2 MnO3-δ Solid Oxide Fuel Cell Electrolyte-Cathode Interface.

    Science.gov (United States)

    Ravella, Uday K; Liu, Jingjing; Corbel, Gwenaël; Skinner, Stephen J; Lacorre, Philippe

    2016-08-23

    Among standard high-temperature cathode materials for solid oxide fuel cells, La0.8 Sr0.2 MnO3-δ (LSM) displays the least reactivity with the oxide-ion conductor La2 Mo2 O9 (LMO), yet a reaction is observed at high processing temperatures, identified by using XRD and focused ion beam secondary-ion mass spectrometry (FIB-SIMS) after annealing at 1050 and 1150 °C. Additionally, Sr and Mn solutions were deposited and annealed on LMO pellets, as well as a Mo solution on a LSM pellet. From these studies several reaction products were identified by using XRD and located by using FIB-SIMS on the surface of pelletised samples. We used depth profiling to show that the reactivity extended up to ∼10 μm from the surface region. If Sr was present, a SrMoO4 -type scheelite phase was always observed as a reaction product, and if Mn was present, LaMnO3+δ single crystals were observed on the surface of the LMO pellets. Additional phases such as La2 MoO6 and La6 MoO12 were also detected depending on the configuration and annealing temperature. Reaction mechanisms and detailed reaction formulae are proposed to explain these observations. The strongest driving force for cationic diffusion appears to originate from Mo(6+) and Mn(3+) cations, rather than from Sr(2+) . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Preparation of submicrocrystal LiMn2O4 used Mn3O4 as precursor and its electrochemical performance for lithium ion battery

    International Nuclear Information System (INIS)

    Liu, Bao-Sheng; Wang, Zhen-Bo; Zhang, Yin; Yu, Fu-Da; Xue, Yuan; Ke, Ke; Li, Fang-Fei

    2015-01-01

    Graphical abstract: Spinal LiMn 2 O 4 particles synthesized at 800 °C for 12 h has the best crystallinity with a submicron size and smallest cation disorder, resulting in a superior capacity retention ratio of 90.4% after 200 cycles at 1 °C at room temperature, which possesses an initial capacity of 106.8 mA h/g. - Highlights: • High purity spinel LiMn 2 O 4 was synthesized from industrial grade raw materials. • LiMn 2 O 4 prepared by optimal conditions has the smallest cation mixing. • Optimized LiMn 2 O 4 has the highest initial capacity with 112.9 mA h/g. • Capacity retention of optimized LiMn 2 O 4 is 90.4% after 200 cycles at 1 °C. - Abstract: Spinel LiMn 2 O 4 has been synthesized by solid state reaction with industrial grade Mn 3 O 4 and Li 2 CO 3 as precursors without purification, and its electrochemical performance for lithium ion battery has been investigated by CR2025 coin cell. The results of X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images show that the size of LiMn 2 O 4 particles grow up with increasing temperature of calcination, and the sample synthesized at 800 °C for 12 h has the best crystallinity with a submicron size. It can deliver initial capacity of 112.9 mA h/g with capacity retention ratio of 89.1% after 200 cycles at charge/discharge rate of 1 C. The results of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) also show that it has the highest electrochemical activity and lowest charge transfer impedance

  11. Calcium Sulfoaluminate Sodalite (Ca 4 Al 6 O 12 SO 4 ) Crystal Structure Evaluation and Bulk Modulus Determination

    KAUST Repository

    Hargis, Craig W.

    2013-12-12

    The predominant phase of calcium sulfoaluminate cement, Ca 4(Al6O12)SO4, was investigated using high-pressure synchrotron X-ray diffraction from ambient pressure to 4.75 GPa. A critical review of the crystal structure of Ca4(Al 6O12)SO4 is presented. Rietveld refinements showed the orthorhombic crystal structure to best match the observed peak intensities and positions for pure Ca4(Al6O 12)SO4. The compressibility of Ca4(Al 6O12)SO4 was studied using cubic, orthorhombic, and tetragonal crystal structures due to the lack of consensus on the actual space group, and all three models provided similar results of 69(6) GPa. With its divalent cage ions, the bulk modulus of Ca4(Al6O 12)SO4 is higher than other sodalites with monovalent cage ions, such as Na8(AlSiO4)6Cl2 or Na8(AlSiO4)6(OH)2·H 2O. Likewise, comparing this study to previous ones shows the lattice compressibility of aluminate sodalites decreases with increasing size of the caged ions. Ca4(Al6O12)SO4 is more compressible than other cement clinker phases such as tricalcium aluminate and less compressible than hydrated cement phases such as ettringite and hemicarboaluminate. © 2013 The American Ceramic Society.

  12. 3-(4-Chlorophenyl-1-[(2R,4aR,8aR-4a,8-dimethyl-1,2,3,4,4a,5,6,8a-octahydronaphthalen-2-yl]prop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Mohamed Tebbaa

    2011-06-01

    Full Text Available The title compound, C21H25ClO, was semi-synthesized from isocostic acid, isolated from the aerial part of Inula Viscosa (L Aiton [or Dittrichia Viscosa (L Greuter]. The cyclohexene ring has a half-chair conformation, whereas the cyclohexane ring displays a chair conformation.

  13. Low-temperature molar heat capacities and entropies of MnO2 (pyrolusite), Mn3O4 (hausmanite), and Mn2O3 (bixbyite)

    Science.gov (United States)

    Robie, R.A.; Hemingway, B.S.

    1985-01-01

    Pyrolusite (MnO2), hausmanite (Mn3O4), and bixbyite (Mn2O3), are important ore minerals of manganese and accurate values for their thermodynamic properties are desirable to understand better the {p(O2), T} conditions of their formation. To provide accurate values for the entropies of these important manganese minerals, we have measured their heat capacities between approximately 5 and 380 K using a fully automatic adiabatically-shielded calorimeter. All three minerals are paramagnetic above 100 K and become antiferromagnetic or ferrimagnetic at lower temperatures. This transition is expressed by a sharp ??-type anomaly in Cpmo for each compound with Ne??el temperatures TN of (92.2??0.2), (43.1??0.2), and (79.45??0.05) K for MnO2, Mn3O4, and Mn2O3, respectively. In addition, at T ??? 308 K, Mn2O3 undergoes a crystallographic transition, from orthorhombic (at low temperatures) to cubic. A significant thermal effect is associated with this change. Hausmanite is ferrimagnetic below TN and in addition to the normal ??-shape of the heat-capacity maxima in MnO2 and Mn2O3, it has a second rounded maximum at 40.5 K. The origin of this subsidiary bump in the heat capacity is unknown but may be related to a similar "anomalous bump" in the curve of magnetization against temperature at about 39 K observed by Dwight and Menyuk.(1) At 298.15 K the standard molar entropies of MnO2, Mn3O4, and Mn2O3, are (52.75??0.07), (164.1??0.2), and (113.7??0.2) J??K-1??mol-1, respectively. Our value for Mn3O4 is greater than that adopted in the National Bureau of Standards tables(2) by 14 per cent. ?? 1985.

  14. Single crystals of the anisotropic Kagome staircase compounds Ni3V2O8 and Co3V2O8

    OpenAIRE

    Balakrishnan, G.; Petrenko, O. A.; Lees, M. R.; Paul, D. McK.

    2004-01-01

    Compounds with a Kagome type lattice are known to exhibit magnetic frustration. Large single crystals of two compounds Ni3V2O8 and Co3V2O8, which are variants of a Kagome net lattice, have been grown successfully by the floating zone technique using an optical image furnace. The single crystals are of high quality and exhibit intriguing magnetic properties.

  15. Quasielastic neutron scattering and infra-red band contour study of H2O reorientations in [Ni(H2O)6] (ClO4)2

    International Nuclear Information System (INIS)

    Janik, J.A.; Janik, J.M.; Otnes, K.; Stanek, T.

    1980-01-01

    IR band contour measurements carried out for [Ni(H 2 O) 6 ] (ClO 4 ) 2 revealed an existence of fast H 2 O 180 deg flips around Ni-O axes at room temperatures. These flips were subjected to a more accurate study by the quasielastic neutron scattering method. Correlation times of the order of picosecond were obtained for room temperatures and the barrier to rotation of ca. 7 kcal/mole. The results are compared to those previously obtained for [Mg(H 2 O) 6 ] (ClO 4 ) 2 and also to those for [Ni(NH 3 ) 6 ] (ClO 4 ) 2 and [Mg(NH 3 ) 6 ] (ClO 4 ) 2 . (author)

  16. Methyl 2-(1a,4a-dimethyl-2,8-dioxo-2,3,4,4a,5,6,7,8-octahydro-1aH-1-oxacyclopropa[d]naphthalen-7-ylacrylate

    Directory of Open Access Journals (Sweden)

    Mohamed Tebbaa

    2012-02-01

    Full Text Available The title compound, C16H20O5, was synthesized from ilicic acid [2-(8-hydroxy-4a,8-dimethyldecahydronaphthalen-2-ylacrylic acid], which was isolated from the chloroform extract of the aerial part of Inula viscose (L Aiton [or Dittrichia viscosa (L Greuter]. The molecule is built up from two fused six-membered rings, the epoxidized six-membered ring adopts a half-chair conformation while the other ring displays a perfect chair conformation. The crystal structure features C—H...O hydrogen bonds.

  17. A study of the complexation of [99mTcO2+] by 2,4-dioxo-1,5,8,12-tetraazacyclotetradecane, 2-oxo-1,5,8,12-tetraazacyclotetradecane and their methylated derivatives in position 3

    International Nuclear Information System (INIS)

    Riche, F.; Vidal, M.; Pasqualini, R.; Duatti, A.

    1992-01-01

    The kinetics of complexation of TcO 2 + by 2,4-dioxo-1,5,8,12-tetraazacyclotetradecane, 2-oxo-1,5,8,12-tetraazacyclotetradecane and their methylated derivatives were studied by reducing 99m TcO 4 - with stannous tartrate. The charges of the complexes obtained were studied by electrophoresis; equilibration studies of the complexes with cyclam and a comparative study of the complexation kinetics have served to demonstrate the remarkable kinetic stability of [1,4,8,11-tetraazacyclotetradecane-TcO 2 + ] and [2-oxo-1,5,8,12-tetraazacyclotetradecane-TcO 2 + ]. (author)

  18. La0.8Sr0.2MnO3

    KAUST Repository

    Wang, Q.; Chen, A. P.; Guo, E. J.; Roldan, M. A.; Jia, Q. X.; Fitzsimmons, M. R.

    2018-01-01

    Using polarized neutron reflectometry, we measured the influence of elastic bending stress on the magnetization depth profile of a La0.8Sr0.2MnO3 (LSMO) epitaxial film grown on a SrTiO3 substrate. The elastic bending strain of +/- 0.03% has no obvious effect on the magnetization depth profile at saturation. This result is in stark contrast to that of (La1-xPrx)(1-y),Ca-y,MnO3 (LPCMO) films for which strain of +/- 0.01% produced dramatic changes in the magnetization profile and Curie temperature. We attribute the difference between the influence of strain on the saturation magnetization in LSMO (weak or none) and LPCMO (strong) to a difference in the ability of LSMO (weak or none) and LPCMO (strong) to phase separate. Our observation provides an upper limit of tuning LSMO saturation magnetization via elastic strain effect.

  19. Two new octahedral/pyramidal frameworks containing both cation channels and lone-pair channels: syntheses and structures of Ba2MnIIMn2III(SeO3)6 and PbFe2(SeO3)4

    International Nuclear Information System (INIS)

    Johnston, Magnus G.; Harrison, William T.A.

    2004-01-01

    The hydrothermal syntheses, single crystal structures, and some properties of Ba 2 Mn II Mn 2 III (SeO 3 ) 6 and PbFe 2 (SeO 3 ) 4 are reported. These related phases contain three-dimensional frameworks of vertex (FeO 6 ) and vertex/edge linked (MnO 6 ) octahedra and SeO 3 pyramids. In each case, the MO 6 /SeO 3 framework encloses two types of 8 ring channels, one of which encapsulates the extra-framework cations and one of which provides space for the Se IV lone pairs. Crystal data: Ba 2 Mn 3 (SeO 3 ) 6 , M r =1201.22, monoclinic, P2 1 /c (No. 14), a=5.4717 (3)A, b=9.0636 (4)A, c=17.6586 (9)A, β=94.519 (1) o , V=873.03 (8)A 3 , Z=2, R(F)=0.031, wR(F 2 )=0.070; PbFe 2 (SeO 3 ) 4 , M r =826.73, triclinic, P1-bar (No. 2), a=5.2318 (5)A, b=6.7925 (6)A, c=7.6445 (7)A, α=94.300 (2) o , β=90.613 (2) o , γ=95.224 (2) o , V=269.73 (4)A 3 , Z=1, R(F)=0.051, wR(F 2 )=0.131

  20. Microwave-enhanced electrochemical cycling performance of the LiNi0.2Mn1.8O4 spinel cathode material at elevated temperature

    CSIR Research Space (South Africa)

    Raju, Kumar

    2016-04-01

    Full Text Available microwave-assisted solid-state reaction has been used to dope LMO with a very low amount of nickel (i.e., LiNi(sub0.2)Mn(sub1.8)O(sub4), herein abbreviated as LMNO) for lithium-ion batteries from Mn(sub3)O(sub4) which is prepared from electrolytic manganese...

  1. New metal-organic polygons involving MM quadruple bonds: M8(O2CtBu)4(mu-SC4H2-3,4-{CO2}2)6 (M=Mo, W).

    Science.gov (United States)

    Byrnes, Matthew J; Chisholm, Malcolm H; Patmore, Nathan J

    2005-12-12

    The reactions between M2(O2CtBu)4, where M=Mo or W, and thienyl-3,4-dicarboxylic acid (0.5-1.5 equiv) in toluene proceed via a series of detectable intermediates to the compounds M8(O2CtBu)4(mu-SC4H2-3,4-{CO2}2)6, which are isolated as air-sensitive yellow (M=Mo) or red (M=W) powders and show parent molecular ions in their mass spectra (MALDI). The structure of the molybdenum complex was determined by single-crystal X-ray crystallography and shown to contain an unusual M8 polygon involving four Mo2 quadruply bonded units linked via the agency of the six 3,4-thienylcarboxylate groups. The structure has crystallographically imposed S4 symmetry and may be described in terms of a highly distorted tetrahedron of Mo2 units or a bisphenoid in which two Mo2 units are linked by a thienyldicarboxylate such that intramolecular Mo2...O bonding is present, while the other thienylcarboxylate bridges merely serve to link these two [Mo2]...[Mo2] units together. The color of the compounds arises from intense M2 delta-to-thienyl pi transitions and, in THF, the complexes are redox-active and show four successive quasi-reversible oxidation waves. The [M8]+ radical cations, generated by one-electron oxidation with AgPF6, are shown to be valence-trapped (class II) by UV-vis-near-IR and electron paramagnetic resonance spectroscopy. These results are supported by the electronic structure calculations on model compounds M8(O2CH)4(mu-SC4H2-3,4-{CO}2)6 employing density functional theory that reveal only a small splitting of the M2 delta manifold via mixing with the 3,4-thienylcarboxylate pi system.

  2. Magnetotransport of CaCu3Mn4O12 complex perovskite derivatives

    International Nuclear Information System (INIS)

    Sanchez-Benitez, J.; Andres, A. de; Garcia-Hernandez, M.; Alonso, J.A.; Martinez-Lope, M.J.

    2006-01-01

    Neutron powder diffraction, magnetic and magnetotransport studies were carried out on new derivatives of the CaCu 3 Mn 4 O 12 (A'A 3 B 4 O 12 ) complex perovskite. The samples were prepared in polycrystalline form under moderate pressure conditions. Substitutions at A and A' sites of CaCu 3 Mn 4 O 12 , with only Mn 4+ and insulating behavior, imply electron doping that affects the magnetic and transport properties. X-ray Absorption Spectroscopy showed that Mn 3+ /Mn 4+ valence mixing occurs only at B site, progressively filling the e g band and providing the metallic character in these compounds, as we observe in most of these samples. A semiconducting behavior is observed in samples with 50% Mn 3+ at B site. This can be understood by the opening of a gap in the conduction band corresponding to the half filling of the e g states. This is the case of the tetravalent rare earth doped samples (Ce and Th at A' site) and of the appropriate A site doped Ca(CuMn 2 )Mn 4 O 12 sample. At the strongly distorted A positions, Mn 3+ , with localized e g electrons, act as magnetic impurities at very low temperatures (<40 K) giving rise to the observed upturn in the resistivity. The magnetic origin of this scattering is evidenced by its drastic reduction under a magnetic field

  3. High-Pressure Phase Relations and Crystal Structures of Postspinel Phases in MgV2O4, FeV2O4, and MnCr2O4: Crystal Chemistry of AB2O4 Postspinel Compounds.

    Science.gov (United States)

    Ishii, Takayuki; Sakai, Tsubasa; Kojitani, Hiroshi; Mori, Daisuke; Inaguma, Yoshiyuki; Matsushita, Yoshitaka; Yamaura, Kazunari; Akaogi, Masaki

    2018-06-04

    We have investigated high-pressure, high-temperature phase transitions of spinel (Sp)-type MgV 2 O 4 , FeV 2 O 4 , and MnCr 2 O 4 . At 1200-1800 °C, MgV 2 O 4 Sp decomposes at 4-7 GPa into a phase assemblage of MgO periclase + corundum (Cor)-type V 2 O 3 , and they react at 10-15 GPa to form a phase with a calcium titanite (CT)-type structure. FeV 2 O 4 Sp transforms to CT-type FeV 2 O 4 at 12 GPa via decomposition phases of FeO wüstite + Cor-type V 2 O 3 . MnCr 2 O 4 Sp directly transforms to the calcium ferrite (CF)-structured phase at 10 GPa and 1000-1400 °C. Rietveld refinements of CT-type MgV 2 O 4 and FeV 2 O 4 and CF-type MnCr 2 O 4 confirm that both the CT- and CF-type structures have frameworks formed by double chains of edge-shared B 3+ O 6 octahedra (B 3+ = V 3+ and Cr 3+ ) running parallel to one of orthorhombic cell axes. A relatively large A 2+ cation (A 2+ = Mg 2+ , Fe 2+ , and Mn 2+ ) occupies a tunnel-shaped space formed by corner-sharing of four double chains. Effective coordination numbers calculated from eight neighboring oxygen-A 2+ cation distances of CT-type MgV 2 O 4 and FeV 2 O 4 and CF-type MnCr 2 O 4 are 5.50, 5.16, and 7.52, respectively. This implies that the CT- and CF-type structures practically have trigonal prism (six-coordinated) and bicapped trigonal prism (eight-coordinated) sites for the A 2+ cations, respectively. A relationship between cation sizes of VIII A 2+ and VI B 3+ and crystal structures (CF- and CT-types) of A 2+ B 2 3+ O 4 is discussed using the above new data and available previous data of the postspinel phases. We found that CF-type A 2+ B 2 3+ O 4 crystallize in wide ionic radius ranges of 0.9-1.4 Å for VIII A 2+ and 0.55-1.1 Å for VI B 3+ , whereas CT-type phases crystallize in very narrow ionic radius ranges of ∼0.9 Å for VIII A 2+ and 0.6-0.65 Å for VI B 3+ . This would be attributed to the fact that the tunnel space of CT-type structure is geometrically less flexible due to the smaller coordination

  4. Enhanced high-potential and elevated-temperature cycling stability of LiMn2O4 cathode by TiO2 modification for Li-ion battery

    International Nuclear Information System (INIS)

    Yu Lihong; Qiu Xinping; Xi Jingyu; Zhu Wentao; Chen Liquan

    2006-01-01

    The surface of spinel LiMn 2 O 4 was modified with TiO 2 by a simple sol-gel method to improve its electrochemical performance at elevated temperatures and higher working potentials. Compared with pristine LiMn 2 O 4 , surface-modification improved the cycling stability of the material. The capacity retention of TiO 2 -modified LiMn 2 O 4 was more than 85% after 60 cycles at high potential cycles between 3.0 and 4.8 V at room temperature and near to 90% after 30 cycles at elevated temperature of 55 deg. C at 1C charge-discharge rate. SEM studies shows that the surface morphology of TiO 2 -modified LiMn 2 O 4 was different from that of pristine LiMn 2 O 4 . Powder X-ray diffraction indicated that spinel was the only detected phase in TiO 2 -modified LiMn 2 O 4 . Introduction of Ti into LiMn 2 O 4 changed the electronic structures of the particle surface. Therefore a surface solid compound of LiTi x Mn 2-x O 4 may be formed on LiMn 2 O 4 . The improved electrochemical performance of surface-modified LiMn 2 O 4 was attributed to the improved stability of crystalline structure and the higher Li + conductivity

  5. Field Dependence of Elastic Constants in the Bilayer Manganite: (La1-z Prz )1.2Sr1.8Mn2O7 for z=0.6

    International Nuclear Information System (INIS)

    Nakanishi, Y.; Shimomura, K.; Matasukawa, M.; Yoshizawa, M.; Apost, M.; Suryanarayanan, R.; Revcolevischi, A.

    2003-01-01

    Elastic properties of the Pr-doped bilayer manganite: (La 1-z Pr z ) 1.2 Sr 1.8 Mn 2 O 7 for z=0.6 was investigated by means of the ultrasonic measurement. No remarkable anomaly was observed around the transition temperature in the temperature dependence of C 33 in zero field. A pronounced elastic anomaly, however, has been observed around the magnetic phase transition field Ht in the longitudinal elastic constants C 11 , indicating the phase can be induced in magnetic fields. The transition accompanies a large hysteresis, implying the ordered state to be so-called ''orbital-glass state''. The origin of observed elastic anomalies are discussed in terms of the coupling between elastic strains and magnetic moments of Mn ions, and a change of carrier numbers. (author)

  6. Detailed single-crystal EPR line shape measurements for the single-molecule magnets Fe8Br and Mn12-acetate

    Science.gov (United States)

    Hill, S.; Maccagnano, S.; Park, Kyungwha; Achey, R. M.; North, J. M.; Dalal, N. S.

    2002-06-01

    It is shown that our multi-high-frequency (40-200 GHz) resonant cavity technique yields distortion-free high-field electron paramagnetic resonance (EPR) spectra for single-crystal samples of the uniaxial and biaxial spin S=10 single-molecule magnets (SMM's) [Mn12O12(CH3COO)16(H2O)4].2CH3COOH.4H2O and [Fe8O2(OH)12(tacn)6]Br8.9H2O. The observed line shapes exhibit a pronounced dependence on temperature, magnetic field, and the spin quantum numbers (MS values) associated with the levels involved in the transitions. Measurements at many frequencies allow us to separate various contributions to the EPR linewidths, including significant D strain, g strain, and broadening due to the random dipolar fields of neighboring molecules. We also identify asymmetry in some of the EPR line shapes for Fe8 and a previously unobserved fine structure to some of the EPR lines for both the Fe8 and Mn12 systems. These findings prove relevant to the mechanism of quantum tunneling of magnetization in these SMM's.

  7. New vanadium tellurites: Syntheses, structures, optical properties of noncentrosymmetric VTeO{sub 4}(OH), centrosymmetric Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10})

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Ming-Li [College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Marsh, Matthew [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Shang, Xian-Xing [College of Chemistry, Fuzhou University, Fuzhou, Fujian 350108 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Mao, Jiang-Gao [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Albrecht-Schmitt, Thomas E. [Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States); Kong, Fang, E-mail: kongfang@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306 (United States)

    2017-05-15

    Two new vanadium tellurites, VTeO{sub 4}(OH) (1) and Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2), have been synthesized successfully with the use of hydrothermal reactions. The crystal structures of the two compounds were determined by single-crystal X-ray diffraction. Compound 1 crystallizes in the polar space group Pca2{sub 1} (No. 29) while compound 2 crystallizes in the centrosymmetric space group C2/c (No. 15). The topography of compound 1 reveals a two-dimensional, layered structure comprised of VO{sub 6} octahedral chains and TeO{sub 3}(OH) zig-zag chains. Compound 2, on the contrary, features a three-dimensional [V{sub 4}O{sub 8}(Te{sub 3}O{sub 10})]{sup 4-} anionic framework with Ba{sup 2+} ions filled into the 10-member ring helical tunnels. The [V{sub 4}O{sub 8}(Te{sub 3}O{sub 10})]{sup 4-} anionic network is the first 3D vanadium tellurite framework to be discovered in the alkaline-earth vanadium tellurite system. Powder second harmonic generation (SHG) measurements indicate that compound 1 shows a weak SHG response of about 0.3×KDP (KH{sub 2}PO{sub 4}) under 1064 nm laser radiation. Infrared spectroscopy, elemental analysis, thermal analysis, and dipole moment calculations have also been carried out. - Graphical abstract: VTeO{sub 4}(OH) (1) crystallizes in the noncentrosymmetric space group Pca2{sub 1} (No. 29) while Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2) crystallizes in the centrosymmetric space group C2/c (No. 15). - Highlights: • VTeO{sub 4}(OH) (1) and Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2) have been synthesized successfully with the use of hydrothermal reactions. • VTeO{sub 4}(OH) (1) crystallizes in the noncentrosymmetric space group Pca2{sub 1} and displays a weak SHG response. • VTeO{sub 4}(OH) (1) represents only the fourth SHG-active material found in vanadium tellurite systems. • Ba{sub 2}V{sub 4}O{sub 8}(Te{sub 3}O{sub 10}) (2) exhibits a novel three-dimensional [V{sub 4}O{sub 8}(Te{sub 3}O{sub 10

  8. Analysis of (Ba,Ca,Sr)3MgSi2O8:Eu2+, Mn2+ phosphors for application in solid state lighting

    International Nuclear Information System (INIS)

    Han, J.K.; Piqutte, A.; Hannah, M.E.; Hirata, G.A.; Talbot, J.B.; Mishra, K.C.; McKittrick, J.

    2014-01-01

    The luminescence properties of Eu 2+ and Mn 2+ co-activated (Ba,Ca,Sr) 3 MgSi 2 O 8 phosphors prepared by combustion synthesis were studied. Eu 2+ -activated (Ba,Ca,Sr) 3 MgSi 2 O 8 has a broad blue emission band centered at 450–485 nm and Eu 2+ –Mn 2+ -activated (Ba,Ca,Sr) 3 MgSi 2 O 8 exhibits a red emission around 620–703 nm, depending on the relative concentrations of Ba, Ca and Sr. The particle size of Eu 2+ and Mn 2+ co-activated (Ba,Ca) 3 MgSi 2 O 8 ranges from 300 nm to 1 μm depending on the metal ion and are agglomerated due to post-synthesis, high temperature annealing. The green emission of Ba 3 MgSi 2 O 8 originates from secondary phases (Ba 2 SiO 4 and BaMgSiO 4 ) confirmed by emission spectra and X-ray diffraction patterns. The secondary phases of Ba 3 MgSi 2 O 8 are removed by the addition of Sr. The quantum efficiencies range from 45% to 70% under 400 nm excitation and the lifetime of red emission of Ba 3 MgSi 2 O 8 decreases significantly with increasing temperature, which is 54% at 400 K of that at 80 K compared to that of blue emission (90% at 400 K of that at 80 K). -- highlights: • (Ba,Ca,Sr) 3 MgSi 2 O 8 :Eu 2+ , Mn 2+ phosphors were prepared by a combustion synthesis method. • The emission spectra consist of broad blue-emission band and red-emission band. • The quantum efficiencies range between 45% and 70%, depending on the relative concentrations of Ba, Ca and Sr. • The secondary phases were eliminated by additions of Sr. • Lifetime of the red-emission decreases with increasing temperature, suggesting that these phosphors are not useful for solid state lighting applications

  9. Substitution and Redox Chemistry of [Bu(4)N](2)[Ta(6)Cl(12)(OSO(2)CF(3))(6)].

    Science.gov (United States)

    Prokopuk, Nicholas; Kennedy, Vance O.; Stern, Charlotte L.; Shriver, Duward F.

    1998-09-21

    Two sequential electrochemical reductions occur for the cluster anion [Ta(6)Cl(12)(OSO(2)CF(3))(6)](2)(-) at 0.89 and 0.29 V vs Ag/AgCl, with the generation [Ta(6)Cl(12)(OSO(2)CF(3))(6)](3)(-) and [Ta(6)Cl(12)(OSO(2)CF(3))(6)](4)(-). Chemical reduction of [Ta(6)Cl(12)(OSO(2)CF(3))(6)](2)(-) by ferrocene produces [Ta(6)Cl(12)(OSO(2)CF(3))(6)](3)(-) with the concomitant shift of the nu(SO(2)) stretch from 1002 to 1018 cm(-)(1). Reaction of [Bu(4)N](2)[Ta(6)Cl(12)(OSO(2)CF(3))(6)] (1) with [Bu(4)N]X (X = Cl, Br, I, NCS) occurs by reduction and substitution, yielding [Bu(4)N](3)[Ta(6)Cl(12)X(6)], where the clusters with X = Br, I, and NCS are new. Spectroscopic (IR and UV-vis) evidence indicates that the reduced cluster core {Ta(6)Cl(12)}(2+) is produced in reaction mixtures of 1 with the halide and pseudohalide ions. Concomitant substitution of the triflate ligands of 1 by X(-) occurs and the rates for the overall reduction and substitution increase in the order X(-) = Cl(-) < Br(-) < NCS(-) < I(-) < CN(-). Reduction of 1 with ferrocene followed by addition of [Bu(4)N]O(2)CCH(3) produces the new cluster [Ta(6)Cl(12)(O(2)CCH(3))(6)](3)(-) isolated as the tetrabutylammonium salt. Cyclic voltammetry and UV-vis spectroscopy on the new clusters [Bu(4)N](3)[Ta(6)Cl(12)X(6)] (X = Br, I, NCS, and O(2)CCH(3)) are reported. Crystal data for [Bu(4)N](3)[Ta(6)Cl(12)(NCS)(6)].CH(2)Cl(2): monoclinic, space group, P2(1)/c (No. 14); a = 25.855(6) Å, b = 21.843(6) Å, c = 16.423(3) Å; beta = 100.03(2) degrees; V = 9133(3) Å(3); Z = 4.

  10. Thermal stability of polyoxometalate compound of Keggin K8[2-SiW11O39]∙nH2O supported with SiO2

    Directory of Open Access Journals (Sweden)

    Yunita Sari M A

    2017-06-01

    Full Text Available Synthesis through sol-gel method and characterization of polyoxometalate compound of K8[b2-SiW11O39]∙nH2O supported with SiO2 have been done. The functional groups of polyoxometalate compound  was characterized by FT-IR spectrophotometer for the fungtional groups and the degree’s of crystalinity  using XRD. The acidity of K8[b2-SiW11O39]∙nH2O/SiO2 was determined qualitative analysis using ammonia and pyridine adsorption and the quantitative analysis using potentiometric titration method. The results of FT-IR spectrum of K8[b2-SiW11O39]∙nH2O appeared at  wavenumber 987.55 cm-1 (W=O, 864.11 cm-1 (W-Oe-W, 756.1 cm-1 (W-Oc-W, 3425.58 cm-1 (O-H, respectively and spectrum of  K8[b2-SiW11O39]SiO2 appeared at wavenumber  956.69 cm-1 (W=O, 864.11 cm-1 (W-Oe-W, 3448.72 cm-1 (O-H, respectively. The diffraction of XRD pattern of K8[b2-SiW11O39]∙nH2O and K8[b2-SiW11O39]∙nH2O/SiO2 compounds show high crystalinity. The acidic properties showed K8[b2-SiW11O39]∙nH2O/SiO2 more acidic compared to K8[b2-The SiW11O39]∙nH2O. The qualitative analysis showed pyridine compound adsorbed more of polyoxometalate compound of K8[b2-SiW11O39]∙nH2O/SiO2. Analysis of stability showed that the K8[b2-SiW11O39]∙nH2O/SiO2 at temperature 500°C has structural changes compare to 200-400oC which was indicated from vibration at wavenumber 800-1000 cm-1. Keywords : K8[b2-SiW11O39]∙nH2O, polyoxometalate, SiO2.

  11. The "1"2C("1"6O,γ"2"8Si) radiative capture reaction at sub-barrier energies

    International Nuclear Information System (INIS)

    Goasduff, A.; Courtin, S.; Haas, F.; Lebhertz, D.; Jenkins, D.G.; Fallis, J.; Ruiz, C.; Hutcheon, D.A.; Amandruz, P.A.; Davis, C.; Hager, U.; Ottewell, D.; Ruprecht, G.

    2014-01-01

    The heavy-ion radiative capture "1"2C("1"6O,γ"2"8Si) was measured at the sub-Coulomb barrier bombarding energy E(lab) = 15.7 MeV, which corresponds to the lowest important resonance observed in the "1"2C + "1"6O fusion excitation function. Thanks to combination of the bismuth germanate (BGO) γ-ray array and the 0 degree DRAGON electromagnetic spectrometer at TRIUMF, the γ-decay spectrum from the entrance channel down to the ground state of "2"8Si was measured. Comparisons of the experimental spectrum to γ spectrum extracted from Monte-Carlo simulations of the complete setup suggest a J"π = 2"+ spin-parity assignment to the entrance channel and yield the radiative capture cross section σ(RC) = 0.22 ± 0.04 μb. Combining this present spin assignment with previous data on radiative capture, a J (J + 1) systematics was constructed, and it indicated a moment of inertia commensurate with the "1"2C+"1"6O grazing angular momentum. Strong dipole transitions are observed from the entrance channel to T = 1 states around 11.5 MeV and are found to result from enhanced M1_I_V transitions to states exhausting a large part of the M1 sum rule built on the ground state of "2"8Si. This specific decay was also reported at bombarding energies close to the Coulomb barrier in our previous study of the "1"2C("1"2C,γ"2"4Mg) heavy-ion radiative capture reaction. Similarities between both systems are investigated. (authors)

  12. Photoluminescence and scintillation properties of Ce-doped Sr2(Gd1-xLux)8(SiO4)6O2 (x = 0.1, 0.2, 0.4, 0.5, 0.6) crystals

    Science.gov (United States)

    Igashira, Takuya; Kawano, Naoki; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

    2018-05-01

    Apatite crystals with chemical compositions of 0.5% Ce-doped Sr2(Gd1-xLux)8(SiO4)6O2 (x = 0.1, 0.2, 0.4, 0.5, 0.6) were synthesized by the Floating Zone method, and then we evaluated their photoluminescence (PL) and scintillation properties. All the Ce-doped samples exhibited PL and scintillation with an intense broad emission in 400-550 nm in which the origin was attributed to the 5d-4f transition of Ce3+, and the emission peak became broader with increasing the concentration of Lu3+. Both PL and scintillation decay time profiles were best-approximated by a sum of two exponential decay functions, and the origin of slower component was attributed to the 5d-4f transition of Ce3+. In the X-ray induced afterglow measurements, the Ce-doped Sr2(Gd0.4Lu0.6)8(SiO4)6O2 sample exhibited the lowest afterglow level. Furthermore, the Ce-doped Sr2(Gd0.5Lu0.5)8(SiO4)6O2 and Sr2(Gd0.4Lu0.6)8(SiO4)6O2 samples showed a clear full energy deposited peak under 5.5 MeV 241Am α-ray irradiation, and the estimated absolute scintillation light yields were around 290 and 1300 ph/5.5 MeV-α, respectively.

  13. Rietveld refinement of the orthorhombic Pbca structures of Rb2CdSi5O12, Cs2MnSiO5O12, Cs2CoSi5O12 and Cs2NiSi5O12 leucites by synchrotron X-ray powder diffraction

    International Nuclear Information System (INIS)

    Bell, A.M.T.; Henderson, C.M.B.

    1996-01-01

    Analysis of high-resolution synchrotron X-ray powder diffraction patterns for hydrothermally synthesized Rb 2 CdSi 5 O 12 and Cs 2 MnSi 5 O 12 leucite analogues, and dry-synthesized Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite analogues showed that they have an orthorhombic Pbca structure. The structures have been refined by the Rietveld method, showing that the tetrahedrally coordinated atoms (Si, Cd, Mn, Co and Ni) are ordered on separate sites. The Cs 2 MnSi 5 O 12 , Cs 2 CoSi 5 O 12 and Cs 2 NiSi 5 O 12 leucite samples are unusual in containing SiO 4 tetrahedra which are more distorted, on average, than the larger MnO 4 , CoO 4 and NiO 4 tetrahedra. The JCPDS file numbers for Rb 2 CdSi 5 O 12 , Cs 2 MnSi 5 O 12 and Cs 2 CoSi 5 O 12 are 46-1491, 46-1492 and 46-1493, respectively. (orig.)

  14. Preparation and characterization of Bi26-2xMn2xMo10O69-d and Bi26.4Mn0.6Mo10-2yMe2yO69-d (Me = V, Fe Solid Solutions

    Directory of Open Access Journals (Sweden)

    Z. A. Mikhaylovskaya

    2017-09-01

    Full Text Available Single phase samples of bismuth molybdate, Bi26Mo10O69, doped with Mn on the bismuth sublattice and V, Fe on the molybdenum sublattice were found to crystallize in the triclinic Bi26Mo10O69 structure at low doping levels and in the monoclinic Bi26Mo10O69 structure - at higher dopant concentration. The assumption that all Mn ions have an oxidation state of +2 was confirmed by means of magnetic measurement results analysis using Curie-Weiss law. Conductivity was investigated using impedance spectroscopy. The conductivity of Bi26.4Mn0.6Mo9.6Fe0.4O69-d was 1.2*10-2 S*cm-1 at 973 K and 2.2*10-4 S*cm-1 at 623 K, and the conductivity of Bi26.4Mn0.6Mo9.2V0.8O69-d was 2.2*10-3 S*cm-1 at 973 K and 2.2*10-5 S*cm-1 at 623 K.

  15. Solid-state synthesis, structure and properties of a novel open-framework cadmium selenite bromide: [Cd10(SeO3)8Br4]·HBr·H2O

    International Nuclear Information System (INIS)

    Chen, Wen-Tong; Wang, Ming-Sheng; Wang, Guan-E; Chen, Hui-Fen; Guo, Guo-Cong

    2013-01-01

    A novel open-framework cadmium selenite bromide, [Cd 10 (SeO 3 ) 8 Br 4 ]·HBr·H 2 O (1), has been obtained by a solid-state reaction at 450 °C, and the structure has been determined by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in Pbcm of the orthorhombic system: a=10.882(3), b=16.275(5), c=18.728(6) Å, V=3317(2) Å 3 , R1/wR2=0.0411/0.0659. Compound 1 is characteristic of a novel 3-D open-framework structure, composing ∞ 2 [CdSeO 3 ] layers and the pillars of edge-shared CdO 3 Br 2 square pyramids. The lattice water molecules and the HBr molecules locate in the voids of the framework. Optical absorption spectrum of 1 reveals the presence of an optical gap of 1.65 eV. Solid-state photoluminescent study indicates that compound 1 exhibits strong violet emission. TG–DSC measurement shows that compound 1 is thermally stable up to 200 °C. - Graphical abstract: A metal selenite halide has been synthesized and features a 3-D open-framework structure, composing edge-shared CdO 8 decahedra and pillars of edge-sharing pentahedra. UV–vis, TG–DSC and luminescent measurements are also reported. Highlights: • This paper reports a novel cadmium selenite bromide obtained by an intermediate-temperature solid-state reaction. • The title compound is characteristic of a novel 3-D open-framework structure, composing ∞ 2 [CdSeO 3 ] layers and the pillars of edge-shared CdO 3 Br 2 square pyramids. • The title compound is thermally stable up to 200 °C. • The title compound has an optical gap of 1.65 eV and exhibits strong violet emission

  16. Vibrational spectra of Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·nH2O (n = 4, 6) with a crystal structure determination of the Tutton salt Cs2Cu(SeO4)2·6H2O

    Science.gov (United States)

    Wildner, M.; Marinova, D.; Stoilova, D.

    2016-02-01

    The solubility in the three-component systems Cs2SO4-CuSO4-H2O and Cs2SeO4-CuSeO4-H2O have been studied at 25 °C. The experimental results show that double salts, Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·4H2O, crystallize from the ternary solutions within large concentration ranges. Crystals of Cs2Cu(SeO4)2·6H2O were synthesized at somewhat lower temperatures (7-8 °C). The thermal dehydration of the title compounds was studied by TG, DTA and DSC methods and the respective dehydration schemes are proposed. The calculated enthalpies of dehydration (ΔHdeh) have values of: 434.2 kJ mol-1 (Cs2Cu(SeO4)2·6H2O), 280.9 kJ mol-1 (Cs2Cu(SeO4)2·4H2O), and 420.2 kJ mol-1 (the phase transition of Cs2Cu(SO4)2·6H2O into Cs2Cu(SO4)2·H2O). The crystal structure of Cs2Cu(SeO4)26H2O was determined from single crystal X-ray diffraction data. It belongs to the group of Tutton salts, crystallizing isotypic to the respective sulfate in a monoclinic structure which is characterized by isolated Cu(H2O)6 octahedra and SeO4 tetrahedra, interlinked by hydrogen bonds and [9]-coordinated Cs+ cations. Infrared spectra of the cesium copper compounds are presented and discussed with respect to both the normal modes of the tetrahedral ions and the water molecules. The analysis of the infrared spectra of the double compounds reveals that the distortion of the selenate tetrahedra in Cs2Cu(SeO4)2·4H2O is stronger than those in Cs2Cu(SeO4)2·6H2O in agreement with the structural data. Matrix-infrared spectroscopy was applied to confirm this claim - Δν3 for SO4 2 - ions matrix-isolated in Cs2Cu(SeO4)2·6H2O has a value of 35 cm-1 and that of the same ions included in Cs2Cu(SeO4)2·4H2O - 84 cm-1. This spectroscopic finding is due to the formation of strong covalent bands Cu-OSO3 on one hand, and on the other to the stronger deformation of the host SeO4 2 - tetrahedra in Cs2Cu(SeO4)2·4H2O as compared to those in Cs2Cu(SeO4)2·6H2O. The strength of the hydrogen bonds as deduced from the

  17. Electrochemical performance of high specific capacity of lithium-ion cell LiV3O8//LiMn2O4 with LiNO3 aqueous solution electrolyte

    International Nuclear Information System (INIS)

    Zhao Mingshu; Zheng Qingyang; Wang Fei; Dai Weimin; Song Xiaoping

    2011-01-01

    Research highlights: → In this paper, the electrochemical performance of aqueous rechargeable lithium battery with LiV 3 O 8 and LiMn 2 O 4 in saturated LiNO 3 electrolyte is studied. → The electrochemical performance tests show that the specific capacity of LiMn 2 O 4 using as the cathode of ARLB is similar to that of ordinary lithium-ion battery with organic electrolyte, which works much better than the formerly reported. → In addition, the cell systems exhibit good cycling performance. Therefore, it has great potential comparing with other batteries such as lead acid batteries and alkaline manganese batteries. - Abstract: The electrochemical performance of aqueous rechargeable lithium battery (ARLB) with LiV 3 O 8 and LiMn 2 O 4 in saturated LiNO 3 electrolyte is studied. The results indicate that these two electrode materials are stable in the aqueous solution and no hydrogen or oxygen produced, moreover, intercalation/de-intercalation of lithium ions occurred within the range of electrochemical stability of water. The electrochemical performance tests show that the specific capacity of LiMn 2 O 4 using as the cathode of ARLB is similar to that of ordinary lithium-ion battery with organic electrolyte, which works much better than the formerly reported. In addition, the cell systems exhibit good cycling performance. Therefore, it has great potential comparing with other batteries such as lead acid batteries and alkaline manganese batteries.

  18. μ-Carbonato-κ(4) O,O':O',O''-bis-{[2'-(di-tert-butyl-phosphan-yl)biphenyl-2-yl-κ(2) P,C (1)]palladium(II)} dichloro-methane monosolvate.

    Science.gov (United States)

    Muller, Alfred; Holzapfel, Cedric W

    2012-12-01

    The title compound, [(μ2-CO3){Pd(P(t-C4H9)2(C12H8)}2]·CH2Cl2, the first CO3-bridged palladium dimer complex reported to date, was obtained while preparing the Pd(0) complex with (2-biphen-yl)P( (t) Bu)2. In the crystal, each palladium dimer is accompanied by a dichloro-methane solvent mol-ecule. Coordination of the carbonate and chelated phosphane ligands gives distorted square-planar environments at the Pd atoms. Important geometrical parameters include Pd-P(av.) = 2.2135 (4) Å, Pd-C(av.) = 1.9648 (16) Å and P-Pd-C = 84.05 (5) and 87.98 (5)°, and O-Pd-O' = 60.56 (4) and 61.13 (4)°. Bonding with the carbonate O atoms shows values of 2.1616 (11) and 2.1452 (11) Å for the Pd-O-Pd bridge, whereas other Pd-O distances are slightly longer at 2.2136 (11) and 2.1946 (11) Å. One of the tert-butyl groups is disordered over two set of sites with an occupancy ratio of 0.723 (6):0.277 (6). Weak C-H⋯O interactions are observed propagating the molecules along the [100] direction.

  19. Mitigation of chromium poisoning of cathodes in solid oxide fuel cells employing CuMn1.8O4 spinel coating on metallic interconnect

    Science.gov (United States)

    Wang, Ruofan; Sun, Zhihao; Pal, Uday B.; Gopalan, Srikanth; Basu, Soumendra N.

    2018-02-01

    Chromium poisoning is one of the major reasons for cathode performance degradation in solid oxide fuel cells (SOFCs). To mitigate the effect of Cr-poisoning, a protective coating on the surface of interconnect for suppressing Cr vaporization is necessary. Among the various coating materials, Cu-Mn spinel coating is considered to be a potential candidate due to their good thermal compatibility, high stability and good electronic conductivity at high temperature. In this study, Crofer 22 H meshes with no protective coating, those with commercial CuMn2O4 spinel coating and the ones with lab-developed CuMn1.8O4 spinel coating were investigated. The lab-developed CuMn1.8O4 spinel coating were deposited on Crofer 22 H mesh by electrophoretic deposition and densified by a reduction and re-oxidation process. With these different Crofer 22 H meshes (bare, CuMn2O4-coated, and CuMn1.8O4-coated), anode-supported SOFCs with Sr-doped LaMnO3-based cathode were electrochemically tested at 800 °C for total durations of up to 288 h. Comparing the mitigating effects of the two types of Cu-Mn spinel coatings on Cr-poisoning, it was found that the performance of the denser lab-developed CuMn1.8O4 spinel coating was distinctly better, showing no degradation in the cell electrochemical performance and significantly less Cr deposition near the cathode/electrolyte interface after the test.

  20. Mianningite, (□,Pb,Ce,Na) (U"4"+,Mn,U"6"+) Fe"3"+_2(Ti,Fe"3"+)_1_8O_3_8, a new member of the crichtonite group from Maoniuping REE deposit, Mianning county, southwest Sichuan, China

    International Nuclear Information System (INIS)

    Ge, Xiangkun; Fan, Guang; Chen, Zhangru; Ai, Yujie; Li, Guowu

    2017-01-01

    Mianningite (IMA 2014-072), ideally (□,Pb,Ce,Na)(U"4"+,Mn,U"6"+) Fe"3"+_2(Ti,Fe"3"+)_1_8O_3_8, is a new member of the crichtonite group from the Maoniuping REE deposit, Mianning county, Sichuan province, China. It was found in fractures of lamprophyre veins and in the contact between lamprophyre and a later quartz-alkali feldspar syenite dyke with REE mineralization, and is named after its type locality. Associated minerals are microcline, albite, quartz, iron-rich phlogopite, augite, muscovite, calcite, baryte, fluorite, epidote, pyrite, magnetite, hematite, galena, hydroxylapatite, titanite, ilmenite, rutile, garnet-group minerals, zircon, allanite-(Ce), monazite-(Ce), bastnaesite-(Ce), parisite-(Ce), maoniupingite-(Ce), thorite, pyrochlore-group minerals and chlorite. Mianningite occurs as opaque subhedral to euhedral tabular crystals, up to 1-2 mm in size, black in color and streak, and with a submetallic luster. Mianningite is brittle, with a conchoidal fracture. Its average micro-indentation hardness is 83.8 kg/mm"2 (load 0.2 kg), which is equivalent to ∝6 on the Mohs hardness scale. Its measured and calculated densities are 4.62 (8) g/cm"3 and 4.77 g/cm"3, respectively. Under reflected light, mianningite is grayish white, with no internal reflections. It appears isotropic and exhibits neither bireflectance nor pleochroism. The empirical formula, calculated on the basis of 38 O atoms per formula unit (apfu), is [□_0_._3_2_2(Pb_0_._2_1_5Ba_0_._0_3_7Sr_0_._0_3_6Ca_0_._0_1_0)_Σ_0_._2_9_8(Ce_0_._1_2_8La_0_._0_7_7Nd_0_._0_1_2)_Σ_0_._2_1_7 (Na_0_._1_2_7K_0_._0_3_6)_Σ_0_._1_6_3]_Σ_0_1_._0_0_0(U"4"+_0_._4_4_7Mn_0_0_._2_9_3U"6 "+_0_._1_1_2Y_0_._0_9_1Zr_0_._0_2_3Th_0_._0_1_1)_Σ_0_._9_7_7(Fe"3"+_1_._2_2_4Fe"2"+_0_._2_4_3Mg_0_._0_2_3P_0_._0_0_8Si_0_._0_0_6 □_0_._4_9_6)_Σ_2_._0_0_0(Ti_1_2_._4_6_4Fe"3"+_5_._2_9_2V"5"+_0_._1_1_8Nb_0_._0_8_3Al_0_._0_2_6Cr"3"+_0_._0_1_7)_Σ_1_8_._0_0_0O_3_8. Mianningite is trigonal, belongs to the space group R anti 3, and has

  1. Synthesis, solid-state structure and supramolecularity of [Cu(pyterpy2](ClO42

    Directory of Open Access Journals (Sweden)

    Mohammed A. Al-Anber

    2015-09-01

    Full Text Available The copper(II polypyridyl complex [Cu(pyterpy2](ClO42 (3 (pyterpy = 4′-(4-pyridyl-2,2′:6,2″-terpyridine was prepared by the reaction of pyterpy (1 with stoichiometric amounts of [Cu(ClO42·6H2O] (2. The progress of the reaction was controlled by FT-IR and UV–vis spectroscopy. The title complex crystallized in the tetragonal space group I4(1/a with unit cell dimensions of a = 8.6277(1, b = 8.6277(1, c = 57.6398(10 Å, V = 4290.55(12 Å3, and Z = 4. The structure of 3 in the solid-state consists of discrete [Cu(pyterpy2]+ ions with copper(II in a distorted octahedral environment setup by two meridional coordinated tripodal 4′-(4-pyridyl-2,2′:6,2″-terpyridine ligands of which the pyridyl unit stays free. Face-to-face π-interactions between terminal coordinated terpy C5N rings link adjacent [Cu(pyterpy2]2+ units resulting in the formation of a 2D-polymer. The geometrical-to-geometrical centroid distance (d is 3.568 Å.

  2. Self-assembled decanuclear Na(I)2Mn(II)4Mn(III)4 complexes: from discrete clusters to 1-D and 2-D structures, with the Mn(II)4Mn(III)4 unit displaying a large spin ground state and probable SMM behaviour.

    Science.gov (United States)

    Langley, Stuart K; Chilton, Nicholas F; Moubaraki, Boujemaa; Murray, Keith S

    2011-12-07

    The synthesis, magnetic characterization and X-ray crystal structures are reported for five new manganese compounds, [Mn(III)(teaH(2))(sal)]·(1/2)H(2)O (1), [Na(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(MeOH)(4)]·6MeOH (2), [Na(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(MeOH)(2)](n)·7MeOH (3), [Na(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(MeOH)(2)](n)·2MeOH·Et(2)O (4) and [K(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(H(2)O)(2)](n)·5MeOH (5). Complex 1 is a mononuclear compound, formed via the reaction of Mn(NO(3))(24H(2)O, triethanolamine (teaH(3)) and salicylic acid (salH(2)) in a basic methanolic solution. Compound 2 is a mixed-valent hetero-metallic cluster made up of a Mn(8)Na(2) decanuclear core and is formed via the reaction of sodium azide (NaN(3)) with 1. Compounds 3-5 are isolated as 1- or 2-D coordination polymers, each containing the decanuclear Mn(8)M(2) (M = Na(+) or K(+)) core building block as the repeating unit. Compound 3 is isolated when 1 is reacted with NaN(3) over a very short reaction time and forms a 1-D coordination polymer. Each unit displays inter-cluster bridges via the O-atoms of teaH(2-) ligands bonding to the sodium ions of an adjacent cluster. Increasing the reaction time appears to drive the formation of 4 which forms 2-D polymeric sheets and is a packing polymorph of 3. The addition of KMnO(4) and NaN(3) to 1 resulted in compound 5, which also forms a 1-D coordination polymer of the decanuclear core unit. The 1-D chains are now linked via inter-cluster potassium and salicylate bridges. Solid state DC susceptibility measurements were performed on compounds 1-5. The data for 1 are as expected for an S = 2 Mn(III) ion, with the isothermal M vs. H data being fitted by matrix diagonalization methods to give values of g and the axial (D) and rhombic (E) zero field splitting parameters of 2.02, -2.70 cm(-1) and 0.36 cm(-1) respectively. The data for 2-5, each with an identical Mn(II)(4)Mn(III)(4

  3. (Zn, Mg)2GeO4:Mn2+ submicrorods as promising green phosphors for field emission displays: hydrothermal synthesis and luminescence properties.

    Science.gov (United States)

    Shang, Mengmeng; Li, Guogang; Yang, Dongmei; Kang, Xiaojiao; Peng, Chong; Cheng, Ziyong; Lin, Jun

    2011-10-07

    (Zn(1-x-y)Mg(y))(2)GeO(4): xMn(2+) (y = 0-0.30; x = 0-0.035) phosphors with uniform submicrorod morphology were synthesized through a facile hydrothermal process. X-Ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL), and cathodoluminescence (CL) spectroscopy were utilized to characterize the samples. SEM and TEM images indicate that Zn(2)GeO(4):Mn(2+) samples consist of submicrorods with lengths around 1-2 μm and diameters around 200-250 nm, respectively. The possible formation mechanism for Zn(2)GeO(4) submicrorods has been presented. PL and CL spectroscopic characterizations show that pure Zn(2)GeO(4) sample shows a blue emission due to defects, while Zn(2)GeO(4):Mn(2+) phosphors exhibit a green emission corresponding to the characteristic transition of Mn(2+) ((4)T(1)→(6)A(1)) under the excitation of UV and low-voltage electron beam. Compared with Zn(2)GeO(4):Mn(2+) sample prepared by solid-state reaction, Zn(2)GeO(4):Mn(2+) phosphors obtained by hydrothermal process followed by high temperature annealing show better luminescence properties. In addition, codoping Mg(2+) ions into the lattice to substitute for Zn(2+) ions can enhance both the PL and CL intensity of Zn(2)GeO(4):Mn(2+) phosphors. Furthermore, Zn(2)GeO(4):Mn(2+) phosphors exhibit more saturated green emission than the commercial FEDs phosphor ZnO:Zn, and it is expected that these phosphors are promising for application in field-emission displays.

  4. High sensitivity cavity ring down spectroscopy of N_2O near 1.22 µm: (II) "1"4N_2"1"6O line intensity modeling and global fit of "1"4N_2"1"8O line positions

    International Nuclear Information System (INIS)

    Tashkun, S.A.; Perevalov, V.I.; Karlovets, E.V.; Kassi, S.; Campargue, A.

    2016-01-01

    In a recent work (Karlovets et al., 2016 [1]), we reported the measurement and rovibrational assignments of more than 3300 transitions belonging to 64 bands of five nitrous oxide isotopologues ("1"4N_2"1"6O, "1"4N"1"5N"1"6O, "1"5N"1"4N"1"6O, "1"4N_2"1"8O and "1"4N_2"1"7O) in the high sensitivity CRDS spectrum recorded in the 7915–8334 cm"−"1 spectral range. The assignments were performed by comparison with predictions of the effective Hamiltonian models developed for each isotopologue. In the present paper, the large amount of measurements from our previous work mentioned above and literature are gathered to refine the modeling of the nitrous oxide spectrum in two ways: (i) improvement of the intensity modeling for the principal isotopologue, "1"4N_2"1"6O, near 8000 cm"−"1 from a new fit of the relevant effective dipole moment parameters, (ii) global modeling of "1"4N_2"1"8O line positions from a new fit of the parameters of the global effective Hamiltonian using an exhaustive input dataset collected in the literature in the 12–8231 cm"−"1 region. The fitted set of 81 parameters allowed reproducing near 5800 measured line positions with an RMS deviation of 0.0016 cm"−"1. The dimensionless weighted standard deviation of the fit is 1.22. As an illustration of the improvement of the predictive capabilities of the obtained effective Hamiltonian, two new "1"4N_2"1"8O bands could be assigned in the CRDS spectrum in the 7915–8334 cm"−"1 spectral range. A line list at 296 K has been generated in the 0–10,700 cm"−"1 range for "1"4N_2"1"8O in natural abundance with a 10"−"3"0 cm/molecule intensity cutoff. - Highlights: • Line parameters of two new "1"4N_2"1"8O bands centered at 7966 cm"−"1 and at 8214 cm"−"1. • Refined sets of the "1"4N_2"1"6O effective dipole moment parameters for ΔP=13,14 series. • Global modeling of "1"4N_2"1"8O line positions and intensities in the 12–8231 cm"−"1 range. • 5800 observed of "1"4N_2"1"8O line positions

  5. A new, high energy rechargeable lithium ion battery with a surface-treated Li1.2Mn0.54Ni0.13Co0.13O2 cathode and a nano-structured Li4Ti5O12 anode

    International Nuclear Information System (INIS)

    Liu, Xiaoyu; Huang, Tao; Yu, Aishui

    2015-01-01

    Through elaborate design, a new rechargeable lithium ion battery has been developed by comprising a surface-treated Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode and a nano-structured Li 4 Ti 5 O 12 anode. After precondition Na 2 S 2 O 8 treatment, the initial coulombic efficiency of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode has been significantly increased and can be compatible with that of the nano-structured Li 4 Ti 5 O 12 anode. The optimization of structure and morphology for both active electrode materials result in their remarkable electrochemical performances in respective lithium half-cells. Ultimately, the rechargeable lithium ion full battery consisting of both electrodes delivers a specific capacity of 99.0 mAh g −1 and a practical energy density of 201 Wh kg −1 , based on the total weight of both active electrode materials. Furthermore, as a promising candidate in the lithium ion battery field, this full battery also achieves highly attractive electrochemical performance with high coulombic efficiency, excellent cycling stability and outstanding rate capability. Thus the proposed battery displays broad practical application prospects for next generation of high-energy lithium ion battery. - Highlights: • The Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode is surface-treated by Na 2 S 2 O 8 . • The nano-sized Li 4 Ti 5 O 12 anode is obtained by a solid-state method. • A new Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 /Li 4 Ti 5 O 12 lithium ion battery is developed. • The battery shows high coulombic efficiency, specific capacity and energy density. • The battery shows high capacity retention rate and good high-rate capability

  6. Long time relaxation of resistance in La0.8Sr0.2MnO3 ceramics and La0.65Ca0.35 MnO3 films on ferroelectric substrates

    International Nuclear Information System (INIS)

    Medvedev, Yu.V.; Mezin, N.I.; Nikolaenko, Yu.M.; Pigur, A.E.; Shishkova, N.V.; Ishchuk, V.M.; Chukanova, I.N.

    2004-01-01

    Galvanomagnetic properties of La 0.65 Ca 0.35 MnO 3 films with a thickness of 0.2 μm on Pb 2.9 Ba 0.05 Sr 0.05 (Zr 0.4 Ti 0.6 )O 3 ferroelectric ceramics substrates have been investigated. We have discovered the monotonic irreversible increase of the film resistance by 3-5 time of value during several hours after multiple inversion of substrate polarization. The long-time relaxation (LTR) of film resistance is explained by dielecrtrization of film intercrystallite boundaries as a result of oxygen redistribution under action of inhomogeneous mechanical stress. In addition, the LTR of resistance of La 0.8 Sr 0.2 MnO 3 and La 0.6 Sr 0.2 Mn 1.2 O 3 ceramic samples has been investigated under action of different kind of mechanical stress: stretch, compression and hydrostatic press. Time dependence of resistance is described by R 0 +ΔRexp(-t/τ). The magnitude of LTR is 5-10 time greater then fast variation of resistance under action of stress. The sign of ΔR is dependent on the kind of stress. The time constant (τ) has the value of 3-9 hours. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Di-?-cyanido-tetra?cyanido(5,5,7,12,12,14-hexa?methyl-1,4,8,11-tetra?aza?cyclo?tetra?decane)[N-(quinolin-8-yl)quinoline-2-carboxamidato]diiron(III)nickel(II) 2.07-hydrate

    OpenAIRE

    Yang, Yuqi; Zhou, Hongbo; Shen, Xiaoping

    2013-01-01

    The asymmetric unit of the title complex, [Fe2Ni(C19H12N3O)2(CN)6(C16H36N4)]?2.07H2O, contains one [Fe(qcq)(CN)3]? anion, half a [Ni(teta)]2+ cation and two partially occupied inter?stitial water mol?ecules [qcq? is the N-(quinolin-8-yl)quinoline-2-carboxamidate anion and teta is 5,5,7,12,12,14-hexa?methyl-1,4,8,11-tetra?aza?cyclo?tetra?deca?ne]. In the complex mol?ecule, two [Fe(qcq)(CN)3]? anions additionally coordinate the central [Ni(teta)]2+ cation through cyanide groups in a trans mode,...

  8. Structure of poly[diaqua[μ-1,2-bis(pyridin-4-ylethane-κ2N:N′]bis(μ3-cyclobutane-1,1-dicarboxylato-κ3O,O′:O′′:O′′′dimanganese(II

    Directory of Open Access Journals (Sweden)

    Do Nam Lee

    2015-08-01

    Full Text Available In the title compound, [Mn(C6H6O4(C12H12N2(H2O]n, the cyclobutane-1,1-dicarboxylate (cbdc ligands bridge three MnII ions, forming layers parallel to the ac plane. These layers are additionally connected by 1,2-bis(pyridin-4-ylethane ligands to form a three-dimensional polymeric framework. An inversion centre is located at the mid-point of the central C—C bond of the 1,2-bis(pyridin-4-ylethane ligand. The coordination geometry of the MnII ion is distorted octahedral and is built up by four carboxylate O atoms, one water O atom and a pyridyl N atom. The pyridine ligand and the coordinating water molecule are in a trans configuration. One carboxylate group of the cbdc ligand acts as a chelating ligand towards one MnII atom, whereas the second carboxylate group coordinates two different MnII atoms.

  9. Metal-insulator transition and magnetic properties of La - (Ba/Ca) - Mn - O compounds

    International Nuclear Information System (INIS)

    Anbarasu, V.; Manigandan, A.; Sathiyakumar, S.; Jayabalan, K.; Kaliyaperumal, L.K.

    2009-01-01

    The manganite compounds La 2 BaMn (3+x) P y (where x = 0, 0.5 and 1) and La 2 CaMn 3 O y have been prepared for the importance in the field of magneto resistance materials through solid-state reaction technique. From the Powder XRD patterns it was confirmed that both compounds were in single phase and the refined crystal system matches with superconducting perovskite structure and the lattice parameters were calculated as a = 3.892( 6) A, b = 3.899(3) A and c = 11.619(8) A for La 2 BaMn 3 O y ; a = 3.851(3) A, b = 3.891(9) A and c = 11.542(7) A for La 2 CaMn 3 O y . The low temperature resistivity measurement reveals that the compound La 2 BaMn 3 O y exhibiting M - I transition and the transition temperature was found to be 270 K. The study on magnetization nature of the La 2 BaMn 3+x Oy (where x = 0, 0.5 and I) compounds through vibrating sample magnetometer confirms the superparamagnetic nature at room temperature condition where as La 2 CaMn 3 O y exhibits paramagnetic nature. The structural relations between the prepared manganite systems La 2 BaMn 3 O y and La 2 CaMn 3 O y with superconducting perovskite compound LaBa 2 Cu 3 O 7-y was studied with the technological application of magneto resistive property of the prepared compounds. (author)

  10. Gd3+-ESR and magnetic susceptibility of GdCu4Al8 and GdMn4Al8

    International Nuclear Information System (INIS)

    Coldea, R.; Coldea, M.; Pop, I.

    1994-01-01

    Gd ESR of GdCu 4 Al 8 and GdMn 4 Al 8 and magnetic susceptibility of GdCu 4 Al 8 , GdMn 4 Al 8 , and YMn 4 Al 8 were measured in the temperature range of 290K--460K and 90K--1050K, respectively. The occurrence of the Mn moment in YMn 4 Al 8 and GdMn 4 Al 8 is strongly correlated with the critical value of d∼2.6 angstrom of the Mn-Mn distance below which the Mn moment is not stable. The experimental data for GdMn 4 Al 8 , compared with the data for the isostructural compounds GdCu 4 Al 8 and YMn 4 Al 8 , show that near the critical value of d, the existence of Mn moment depends not only on the value of d, but also on the local magnetic surroundings. It has been revealed that the magnetic character of Mn moment in YMn 4 Al 8 and GdMn 4 Al 8 changes from an itinerant electron type to a local-moment type with increasing temperature

  11. Interfacial reactions of Ba{sub 2}YCu{sub 3}O{sub 6+z} with coated conductor buffer layer, LaMnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Liu, G. [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Wong-Ng, W., E-mail: winnie.wong-ng@nist.go [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Kaduk, J.A. [Poly Crystallography Inc., Naperville, IL 60540 (United States); Cook, L.P. [Ceramics Division, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States)

    2010-03-01

    Chemical interactions between the Ba{sub 2}YCu{sub 3}O{sub 6+x} superconductor and the LaMnO{sub 3} buffer layers employed in coated conductors have been investigated experimentally by determining the phases formed in the Ba{sub 2}YCu{sub 3}O{sub 6+x}-LaMnO{sub 3} system. The Ba{sub 2}YCu{sub 3}O{sub 6+x}-LaMnO{sub 3} join within the BaO-(Y{sub 2}O{sub 3}-La{sub 2}O{sub 3})-MnO{sub 2}-CuO{sub x} multi-component system is non-binary. At 810 deg. C (p{sub O2} = 100 Pa) and at 950 deg. C in purified air, four phases are consistently present along the join, namely, Ba{sub 2-x}(La{sub 1+x-y}Y{sub y})Cu{sub 3}O{sub 6+z}, Ba(Y{sub 2-x}La{sub x})CuO{sub 5}, (La{sub 1-x}Y{sub x})MnO{sub 3}, (La,Y)Mn{sub 2}O{sub 5}. The crystal chemistry and crystallography of Ba(Y{sub 2-x}La{sub x})CuO{sub 5} and (La{sub 1-x}Y{sub x})Mn{sub 2}O{sub 5} were studied using the X-ray Rietveld refinement technique. The Y-rich and La-rich solid solution limits for Ba(Y{sub 2-x}La{sub x})CuO{sub 5} are Ba(Y{sub 1.8}La{sub 0.2})CuO{sub 5} and Ba(Y{sub 0.1}La{sub 1.9})CuO{sub 5}, respectively. The structure of Ba(Y{sub 1.8}La{sub 0.2})CuO{sub 5} is Pnma (No. 62), a = 12.2161(5) A, b = 5.6690(2) A, c = 7.1468(3) A, V = 494.94(4) A{sup 3}, and D{sub x} = 6.29 g cm{sup -3}. YMn{sub 2}O{sub 5} and LaMn{sub 2}O{sub 5} do not form solid solution at 810 deg. C (p{sub O2} = 100 Pa) or at 950 deg. C (in air). The structure of YMn{sub 2}O{sub 5} was confirmed to be Pbam (No. 55), a = 7.27832(14) A, b = 8.46707(14) A, c = 5.66495(10) A, and V = 349.108(14) A{sup 3}. A reference X-ray pattern was prepared for YMn{sub 2}O{sub 5}.

  12. Electrochemically active MnO{sub 2} coated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} cathode with highly improved initial coulombic efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Yanling; Xu, Youlong, E-mail: ylxu@mail.xjtu.edu.cn; Sun, Xiaofei; Xiong, Lilong; Mao, Shengchun

    2016-10-30

    Highlights: • MnO{sub 2} was used to coat lithium-rich layered oxide Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2}. • MnO{sub 2} is electrochemically active and became spinel phase after cycles. • MnO{sub 2}-coated material shows noticeably improved initial coulombic efficiency. • Specific capacities and rate performances could also be enhanced by MnO{sub 2} coating. - Abstract: Lithium-rich layered oxide is known to be one of the most promising positive electrode materials for lithium ion batteries due to its large capacity and high energy density. However, low initial coulombic efficiency is currently an urgent problem hindering its practical application. In this work, electrochemically active MnO{sub 2} coating was used to improve the coulombic efficiency of Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2}. Firstly, the pristine material was synthesized via co-precipitation following by solid-state calcination. Then MnO{sub 2}-coated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} was prepared by heat treatment of the mixture of pristine powder and manganese nitrate. During first discharging, lithium ions can intercalate into not only the delithiated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} but also the MnO{sub 2} coating, thus noticeably improves the coulombic efficiency and discharge capacity. The initial efficiency is enhanced from 61.2% (pristine) to 84.4%, 88.8% and 95.4%, respectively, for 10 wt.%, 15 wt.% and 20 wt.% MnO{sub 2} coated Li{sub 1.2}Ni{sub 0.18}Co{sub 0.04}Mn{sub 0.58}O{sub 2} at 20 mA g{sup −1}. Furthermore, the 15 wt.% MnO{sub 2} coated sample delivers an initial discharge capacity as high as 294.4 mAh g{sup −1}.

  13. Rational synthesis of high nuclearity Mo/Fe/S clusters: the reductive coupling approach in the convenient synthesis of (Cl(4)-cat)(2)Mo(2)Fe(6)S(8)(PR(3))(6) [R = Et, (n)Pr, (n)Bu] and the new [(Cl(4)-cat)(2)Mo(2)Fe(2)S(3)O(PEt(3))(3)Cl]-1/2(Fe(PEt(3))(2)(MeCN)(4)) and (Cl(4)-cat)(2)Mo(2)Fe(3)S(5)(PEt(3))(5) clusters.

    Science.gov (United States)

    Han, J; Koutmos, M; Ahmad, S A; Coucouvanis, D

    2001-11-05

    A general method for the synthesis of high nuclearity Mo/Fe/S clusters is presented and involves the reductive coupling of the (Et(4)N)(2)[(Cl(4)-cat)MoOFeS(2)Cl(2)] (I) and (Et(4)N)(2)[Fe(2)S(2)Cl(4)] (II) clusters. The reaction of I and II with Fe(PR(3))(2)Cl(2) or sodium salts of noncoordinating anions such as NaPF(6) or NaBPh(4) in the presence of PR(3) (R = Et, (n)Pr, or (n)Bu) affords (Cl(4)-cat)(2)Mo(2)Fe(6)S(8)(PR(3))(6) [R = Et (IIIa), (n)Pr (IIIb), (n)Bu (IIIc)], Fe(6)S(6)(PEt(3))(4)Cl(2) (IV) and (PF(6))[Fe(6)S(8)(P(n)Pr(3))(6)] (V) as byproducts. The isolation of (Et(4)N)[Fe(PEt(3))Cl(3)] (VI), NaCl, and SPEt(3) supports a reductive coupling mechanism. Cluster IV and V also have been synthesized by the reductive self-coupling of compound II. The reductive coupling reaction between I and II by PEt(3) and NaPF(6) in a 1:1 ratio produces the (Et(4)N)(2)[(Cl(4)-cat)Mo(L)Fe(3)S(4)Cl(3)] clusters [L = MeCN (VIIa), THF (VIIb)]. The hitherto unknown [(Cl(4)-cat)(2)Mo(2)Fe(2)S(3)O(PEt(3))(3)Cl](+) cluster (VIII) has been isolated as the 2:1 salt of the (Fe(PEt(3))(2)(MeCN)(4))(2+) cation after the reductive self-coupling reaction of I in the presence of Fe(PEt(3))(2)Cl(2). Cluster VIII crystallizes in the monoclinic space group P2(1)/c with a = 11.098(3) A, b = 22.827(6) A, c = 25.855(6) A, beta = 91.680(4) degrees, and Z = 4. The formal oxidation states of metal atoms in VIII have been assigned as Mo(III), Mo(IV), Fe(II), and Fe(III) on the basis of zero-field Mössbauer spectra. The Fe(PEt(3))(2)(MeCN)(4) cation of VIII is also synthesized independently, isolated as the BPh(4)(-) salt (IX), and has been structurally characterized. The reductive coupling of compound I also affords in low yield the new (Cl(4)-cat)(2)Mo(2)Fe(3)S(5)(PEt(3))(5) cluster (X) as a byproduct. Cluster X crystallizes in the monoclinic space group P2(1)/n with a = 14.811(3) A, b = 22.188(4) A, c = 21.864(4) A, beta = 100.124(3) degrees, and Z = 4 and the structure shows very short Mo

  14. (2-Formyl-6-methoxyphenolato-κ2O1,O2(perchlorato-κO(1,10-phenanthroline-κ2N,N′copper(II

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    Zhi-Yong Wu

    2008-05-01

    Full Text Available In the title molecule, [Cu(C8H7O3(ClO4(C12H8N2], the CuII ion is five-coordinated by two N atoms [Cu—N = 1.995 (3 and 2.022 (3 Å] from a 1,10-phenanthroline ligand, two O atoms [Cu—O = 1.908 (2 and 1.927 (2 Å] from an o-vanillin ligand and one O atom [Cu—O = 2.510 (3 Å] from a perchlorate anion in a distorted square-pyramidal geometry. Three O atoms of the perchlorate anion are rotationally disordered between two orientations, with occupancies of 0.525 (13 and 0.475 (13. In the crystal structure, two molecules related by a centre of symmetry are paired in such a way that the phenolate O atom from one molecule completes the distorted octahedral Cu coordination in another molecule [Cu...O = 2.704 (2 Å].

  15. Simultaneous stabilization/solidification of Mn2+ and NH4+-N from electrolytic manganese residue using MgO and different phosphate resource.

    Science.gov (United States)

    Shu, Jiancheng; Wu, Haiping; Liu, Renlong; Liu, Zuohua; Li, Bing; Chen, Mengjun; Tao, Changyuan

    2018-02-01

    This study examined simultaneous stabilization and solidification (S/S) of Mn 2+ and NH 4 + -N from electrolytic manganese residue (EMR) using MgO and different phosphate resource. The characteristics of EMR NH 4 + -N and Mn 2+ S/S behavior, S/S mechanisms, leaching test and economic analysis, were investigated. The results show that the S/S efficiency of Mn 2+ and NH 4 + -N could reach 91.58% and 99.98%, respectively, and the pH value is 8.75 when the molar ratio of Mg:P is 3:1 and the dose of PM (MgO and Na 3 PO 4 ·12H 2 O) is 8wt%. In this process, Mn 2+ could mainly be stabilized in the forms of Mn(H 2 PO 4 ) 2 ·2H 2 O, Mn 3 (PO 4 ) 2 ·3H 2 O, Mn(OH) 2 , and MnOOH, and NH 4 + -N in the form of NH 4 MgPO 4 ·6H 2 O. Economic evaluation indicates that using PM process has a lower cost than HPM and HOM process for the S/S of Mn 2+ and NH 4 + -N from EMR at the same stabilization agent dose. Leaching test values of all the measured metals are within the permitted level for the GB8978-1996 test suggested when the dose of PM, HPM and HOM is 8wt%. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Hydrothermal synthesis, thermal, structural, spectroscopic and magnetic studies of the Mn5-x Co x (HPO4)2(PO4)2(H2O)4 (x=1.25, 2, 2.5 and 3) finite solid solution

    International Nuclear Information System (INIS)

    Larrea, Edurne S.; Mesa, Jose L.; Pizarro, Jose L.; Arriortua, Maria I.; Rojo, Teofilo

    2007-01-01

    The Mn 5- x Co x (HPO 4 ) 2 (PO 4 ) 2 (H 2 O) 4 (x=1.25, 2, 2.5, 3) finite solid solution has been synthesized by mild hydrothermal conditions under autogeneous pressure. The phases crystallize in the C2/c space group with Z=4, belonging to the monoclinic system. The unit-cell parameters obtained from single crystal X-ray diffraction are: a=17.525(1), b=9.0535(6), c=9.4517(7) A, β=96.633(5) o being R1=0.0436, wR2=0.0454 for Mn75Co25; a=17.444(2), b=9.0093(9), c=9.400(1) A, β=96.76(1) o being R1=0.0381, wR2=0.0490 for Mn60Co40; a=17.433(2), b=8.9989(9), c=9.405(1) A, β=96.662(9) o being R1=0.0438, wR2=0.0515 for Mn50Co50 and a=17.4257(9), b=8.9869(5), c=9.3935(5) A, β=96.685(4) o being R1=0.0296, wR2=0.0460 for Mn40Co60. The structure consists of a three dimensional network formed by octahedral pentameric entities (Mn,Co) 5 O 16 (H 2 O) 6 sharing vertices with the (PO 4 ) 3- and (HPO 4 ) 2- tetrahedra. The limit of thermal stability of these compounds is, approximately, 165 deg. C, near to this mean temperature the phases loose their water content in two successive steps. IR spectra show the characteristic bands of the water molecules and the phosphate and hydrogen-phosphate oxoanions. The diffuse reflectance spectra are consistent with the presence of MO 6 octahedra environments in slightly distorted octahedral geometry, except for the M(3)O 6 octahedron which presents a remarkable distortion and so a higher Dq parameter. The mean value for the Dq and B-Racah parameter for the M(1),(2)O 6 octahedra is 685 and 850 cm -1 , respectively. These parameters for the most distorted M(3)O 6 polyhedron are 825 and 880 cm -1 , respectively. The four phases exhibit antiferromagnetic couplings as the major magnetic interactions. However, a small spin canting phenomenon is observed at low temperatures for the two phases with major content in the anisotropic-Co(II) cation. - Graphical abstract: Crystal structure of the finite solid solution Mn 5-x Co x (HPO 4 ) 2 (PO 4 ) 2 (H

  17. rac-6-Hydroxy-4-(4-nitrophenyl-5-(2-thienylcarbonyl-6-(trifluoromethyl-3,4,5,6-tetrahydropyrimidin-2(1H-one monohydrate

    Directory of Open Access Journals (Sweden)

    Jian-Li Zhang

    2010-11-01

    Full Text Available The title compound, C16H12F3N3O5S·H2O, was prepared by reaction of 4-nitrobenzaldehyde, 4,4,4-trifluoro-1-(thiophen-2-ylbutane-1,3-dione and urea. The asymmetric unit contains two independent molecules, with essentially identical geometries and conformations. The dihydropyrimidine rings adopt a half-chair conformation. The dihedral angles between the benzene ring and the thiophene ring are 54.82 (8 and 58.72 (8° in the two molecules. The molecular conformation of one of the molecules is stabilized by two intramolecular O—H...O hydrogen bonds, generating an S(6 ring. The crystal structure is stabilized by intermolecular O—H...O and N—H...O hydrogen bonds.

  18. Temperature-controlled formation of Anderson-type compounds and their conversion to [γ-Mo{sub 8}O{sub 26}]{sup 4-}-based variants using pendent ligands

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Ai-xiang; Li, Ting-ting; Tian, Yan; Ni, Huai-ping; Ji, Xue-bin; Liu, Jia-ni; Liu, Guo-cheng; Ying, Jun [Bohai Univ., Jinzhou (China). Dept. of Chemistry

    2017-10-01

    By tuning the reaction temperature, two Anderson- and two [γ-Mo{sub 8}O{sub 26}]{sup 4-}-based compounds decorated by pendent organic ligands, [Cu{sup II}{sub 9}(bpz){sub 2}(pz){sub 2}(H{sub 2}O){sub 24}]-[H{sub 2}(Cr(OH){sub 5}Mo{sub 6}O{sub 19}){sub 4}].11H{sub 2}O (1), [Cu{sup II}(bpz){sub 2}(H{sub 2}O){sub 2}(γ-H{sub 4}-Mo{sub 8}O{sub 26})].2H{sub 2}O (2), [Cu{sup II}{sub 2}(tea){sub 2}(H{sub 2}O){sub 6}(HCr(OH){sub 6}Mo{sub 6}O{sub 18}){sub 2}]. 6H{sub 2}O (3) and [Ag{sup I}(bpz)(H{sub 2}O)(γ-H{sub 4}Mo{sub 8}O{sub 26}){sub 0.5}] (4) (bpz=4-butyl-1H-pyrazole, pz=1H-pyrazole, tea=2-[1,2,4]triazol-4-yl-ethylamine), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis, IR spectra and elemental analyses. In compound 1, there are two kinds of tri-nuclear Cu{sup II} clusters induced by bpz and pz ligands, respectively. Four Anderson-type anions are linked by these tri-nuclear clusters to form a ''W''-type subunit. In compound 2, the [Cu(bpz){sub 2}(H{sub 2}O){sub 2}]{sup 2+} subunits connect the γ-Mo{sub 8} anions to construct a chain. The remaining two non-coordinated N donors in [Cu(bpz){sub 2}(H{sub 2}O){sub 2}]{sup 2+} further link two adjacent γ-Mo{sub 8} anions through Mo-N bonds. In compound 3, there exists a bi-nuclear Cu{sup II} cluster [Cu{sub 2}(tea){sub 2}(H{sub 2}O){sub 6}]{sup 4+}. The discrete bi-nuclear Cu{sup II} clusters and the CrMo{sub 6} anions link each other through abundant hydrogen bonding interactions. In compound 4, the [Ag(bpz)(H{sub 2}O)]{sup +} subunits connect γ-Mo{sub 8} anions to build a zigzag chain. The chains are further fused by other [Ag(bpz)(H{sub 2}O)]{sup +} cations to form a grid-like layer. There still exist Mo-N bonds in 4. We also have investigated the electrochemical and photocatalytic properties of 1-4.

  19. 1-O-Acetyl-3,4,6-tri-O-benzyl-2-C-bromomethyl-2-deoxy-α-d-glucopyranose

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    Henok H. Kinfe

    2013-01-01

    Full Text Available In the title compound, C30H33BrO6, the pyranose ring adopts a chair conformation. Two of the O-benzyl phenyl rings lie almost perpendicular to C/C/C/O plane formed by the ring atoms not attached to these O-benzyl phenyl rings, and form dihedral angles of 85.1 (2 and 64.6 (2°, while the third O-benzyl phenyl ring is twisted so that it makes a dihedral angle 34.9 (2° to this C/C/C/O plane. This twist is ascribed to the formation of an S(8 loop stabilized by a weak intramolecular C—H...O hydrogen bond.

  20. (2aR*,5S*,6aS*,8aS*,E-Ethyl 5-hydroxy-7,7,8a-trimethyl-8-oxo-2,2a,6,6a,7,8,8a,8b-octahydro-1H-pentaleno[1,6-bc]oxepine-4-carboxylate

    Directory of Open Access Journals (Sweden)

    Goverdhan Mehta

    2012-12-01

    Full Text Available The title compound, C17H24O5, featuring a 2-carbethoxy-3-oxepanone unit in its intramolecularly O—H...O hydrogen-bonded enol form, was obtained via [(CF3CO22Rh]2-catalysed intramolecular O—H bond insertion in the α-diazo-ω-hydroxy-β-ketoester, ethyl 4-[(1S,3aS,6R,6aS-6-hydroxy-2,2,3a-trimethyl-3-oxo-octahydropentalen-1-yl]-2-diazo-3-oxobutanoate. The seven-membered oxacyclic ring, thus constructed on a cis-fused diquinane platform, was found to adopt a distorted boat–sofa conformation.

  1. 2,2′-Bis{8-[(benzylaminomethylidene]-1,6-dihydroxy-5-isopropyl-3-methylnaphthalen-7(8H-one}

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    Shukhrat M. Hakberdiev

    2013-11-01

    Full Text Available The asymmetric unit of the title compound, C44H44N2O6, contains two independent molecules with similar conformations. The dihydronaphthalene ring systems are approximately planar [maximum deviations = 0.036 (2, 0.128 (2, 0.0.24 (2 and 0.075 (2 Å]. The dihedral angle between two dihydronaphthalene ring systems is 83.37 (4° in one molecule and 88.99 (4° in the other. The carbonyl O atom is linked with the adjacent hydroxy and imino groups via intramolecular O—H...O and N—H...O hydrogen bonds. In the crystal, molecules are linked through O—H...O hydrogen bonds into layers parallel to (001, and adjacent layers are further stacked by π–π interactions between dihydronaphthalene and phenyl rings into a three-dimensional supramolecular architecture. In the crystal, one of the isopropyl groups is disordered over two positions with an occupancy ratio of 0.684 (8:0.316 (8.

  2. Synthesis, structure, and spectroscopic and magnetic characterization of [Mn12O12(O2CCH2But)16(MeOH)4]·MeOH, a Mn12 single-molecule magnet with true axial symmetry.

    Science.gov (United States)

    Lampropoulos, Christos; Murugesu, Muralee; Harter, Andrew G; Wernsdofer, Wolfgang; Hill, Stephen; Dalal, Naresh S; Reyes, Arneil P; Kuhns, Philip L; Abboud, Khalil A; Christou, George

    2013-01-07

    The synthesis and properties are reported of a rare example of a Mn(12) single-molecule magnet (SMM) in truly axial symmetry (tetragonal, I4). [Mn(12)O(12)(O(2)CCH(2)Bu(t))(16)(MeOH)(4)]·MeOH (3·MeOH) was synthesized by carboxylate substitution on [Mn(12)O(12)(O(2)CMe)(16)(H(2)O)(4)]·2MeCO(2)H·4H(2)O (1). The complex was found to possess an S = 10 ground state, as is typical for the Mn(12) family, and displayed both frequency-dependent out-of-phase AC susceptibility signals and hysteresis loops in single-crystal magnetization vs DC field sweeps. The loops also exhibited quantum tunneling of magnetization steps at periodic field values. Single-crystal, high-frequency electron paramagnetic resonance spectra on 3·MeOH using frequencies up to 360 GHz revealed perceptibly sharper signals than for 1. Moreover, careful studies as a function of the magnetic field orientation did not reveal any satellite peaks, as observed for 1, suggesting that the crystals of 3 are homogeneous and do not contain multiple Mn(12) environments. In the single-crystal (55)Mn NMR spectrum in zero applied field, three well-resolved peaks were observed, which yielded hyperfine and quadrupole splitting at three distinct sites. However, observation of a slight asymmetry in the Mn(4+) peak was detectable, suggesting a possible decrease in the local symmetry of the Mn(4+) site. Spin-lattice (T(1)) relaxation studies were performed on single crystals of 3·MeOH down to 400 mK in an effort to approach the quantum tunneling regime, and fitting of the data using multiple functions was employed. The present work and other recent studies continue to emphasize that the new generation of truly high-symmetry Mn(12) complexes are better models for thorough investigation of the physical properties of SMMs than their predecessors such as 1.

  3. Molecular assembly and magnetic dynamics of two novel Dy6 and Dy8 aggregates.

    Science.gov (United States)

    Guo, Yun-Nan; Chen, Xiao-Hua; Xue, Shufang; Tang, Jinkui

    2012-04-02

    Complexation of dysprosium(III) with the heterodonor chelating ligand o-vanillin picolinoylhydrazone (H(2)ovph) in the presence of a carbonato ligand affords two novel Dy(6) and Dy(8) clusters, namely, [Dy(6)(ovph)(4)(Hpvph)(2)Cl(4)(H(2)O)(2)(CO(3))(2)]·CH(3)OH·H(2)O·CH(3)CN (2) and [Dy(8)(ovph)(8)(CO(3))(4)(H(2)O)(8)]·12CH(3)CN·6H(2)O (3). Compound 2 is composed of three petals of the Dy(2) units linked by two carbonato ligands, forming a triangular prism arrangement, while compound 3 possesses an octanuclear core with an unprecedented tub conformation, in which Dy(ovph) fragments are attached to the sides of the carbonato core. The static and dynamic magnetic properties are reported and discussed. In the Dy(6) aggregate, three Dy(2) "skeletons", having been well preserved (see the scheme), contribute to the single-molecule-magnet behavior with a relatively slow tunneling rate, while the Dy(8) cluster only exhibits a rather small relaxation barrier.

  4. Synthesis and Characterization of 8-Yttrium(III-Containing 81-Tungsto-8-Arsenate(III, [Y8(CH3COO(H2O18(As2W19O684(W2O62(WO4]43−

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    Masooma Ibrahim

    2015-06-01

    Full Text Available The 8-yttrium(III-containing 81-tungsto-8-arsenate(III [Y8(CH3COO(H2O18(As2W19O684(W2O62(WO4]43− (1 has been synthesized in a one-pot reaction of yttrium(III ions with [B-α-AsW9O33]9− in 1 M NaOAc/HOAc buffer at pH 4.8. Polyanion 1 is composed of four {As2W19O68} units, two {W2O10} fragments, one {WO6} group, and eight YIII ions. The hydrated cesium-sodium salt of 1 (CsNa-1 was characterized in the solid-state by single-crystal XRD, FT-IR spectroscopy, thermogravimetric and elemental analyses.

  5. K0.78Na0.22MoO2AsO4

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    Ahmed Driss

    2013-08-01

    Full Text Available The title compound, potassium sodium dioxidomolybdenum(VI arsenate, K0.78Na0.22MoO2AsO4, was synthesized by a solid-state reaction route. The structure is built up from corner-sharing MoO6 octahedra and AsO4 tetrahedra, creating infinite [MoAsO8]∞ chains running along the b-axis direction. As, Mo and all but one O atom are on special positions (4c with m symmetry and K (occupancy 0.78 is on a position (4a of -1 in the tunnels. The possible motion of the alkali cations has been investigated by means of the bond-valance sum (BVS model. The simulation shows that the Na+ motion appears to be easier mainly along the b-axis direction. Structural relationships between the different compounds of the AMoO2AsO4 (A = Ag, Li, Na, K, Rb series and MXO8 (M = V; X = P, As chains are discussed.

  6. The Influence of Deposition Methods of Support Layer on Cordierite Substrate on the Characteristics of a MnO2–NiO–Co3O4/Ce0.2Zr0.8O2/Cordierite Three Way Catalyst

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    Phuong Thi Mai Pham

    2014-09-01

    Full Text Available This paper compares different coating methods (in situ solid combustion, hybrid deposition, secondary growth on seed, suspension, double deposition of wet impregnation and suspension to deposit Ce0.2Zr0.8O2 mixed oxides on cordierite substrates, for use as a three way catalyst. Among them, the double deposition was proven to be the most efficient one. The coated sample shows a BET (Brunauer–Emmett–Teller surface area of 25 m2/g, combined with a dense and crack free surface. The catalyst with a layer of MnO2–NiO–Co3O4 mixed oxides on top of the Ce0.2Zr0.8O2/cordierite substrate prepared by this method exhibits good activity for the treatment of CO, NO and C3H6 in exhaust gases (CO conversion of 100% at 250 °C, C3H6 conversion of 100% at 400 °C and NO conversion of 40% at 400 °C.

  7. (1S,3R,8S,9R,10S-2,2-Dichloro-3,7,7,10-tetramethyl-9,10-epoxytricyclo[6.4.0.01,3]dodecane

    Directory of Open Access Journals (Sweden)

    Moha Berraho

    2010-12-01

    Full Text Available The title compound, C16H24Cl2O, was synthesized from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene, which was isolated from the essential oil of the Atlas cedar (cedrus atlantica. The molecule forms an extended sheet of two fused rings which exhibit different conformations. The six-membered ring has a half-chair conformation, while the seven-membered ring displays a chair conformation; the dihedral angle between the two rings is 38.2 (1°.

  8. Giant room-temperature magnetoresistance in La0.8Tb0.2MnO3 under the low magnetic fields

    International Nuclear Information System (INIS)

    Zhang Yingtang; Chen Ziyu; Wang Chunchang; Jie Qiu; Lue Huibin

    2009-01-01

    Polycrystalline perovskite La 0.8 Tb 0.2 MnO 3 (LTMO) with an orthorhombic phase was synthesized by conventional solid-state reaction. The magnetic and electric properties of La 0.8 Tb 0.2 MnO 3 were examined. The striking finding is that the material exhibits giant magnetoresistance at room temperature as high as -31.8% and -35.7% under the low magnetic fields of 100 and 1000 Oe, respectively. This result suggests that La 0.8 Tb 0.2 MnO 3 has a promising potential in future device developments

  9. Photoemission study of absorption mechanisms in Bi2.0Sr1.8Ca0.8La0.3Cu2.1O8+δ, BaBiO3, and Nd1.85Ce0.15CuO4

    International Nuclear Information System (INIS)

    Lindberg, P.A.P.; Shen, Z.; Wells, B.O.; Dessau, D.S.; Ellis, W.P.; Borg, A.; Kang, J.; Mitzi, D.B.; Lindau, I.

    1989-01-01

    Photoemission measurements in the constant-final-state (absorption) mode were performed on three different classes of high-temperature superconductors Bi 2.0 Sr 1.8 Ca 0.8 La 0.3 Cu 2.1 O 8+δ , BaBiO 3 , and Nd 1.85 Ce 0.15 CuO 4 using synchrotron radiation from 20 to 200 eV. Absorption signals from all elements but Ce are identified. The results firmly show that the Bi 6s electrons are more delocalized in BaBiO 3 than in Bi 2.0 Sr 1.8 Ca 0.8 La 0.3 Cu 2.1 O 8+δ , in agreement with the results of band-structure calculations. Differences in the absorption signals due to O and Bi excitations between BaBiO 3 and Bi 2.0 Sr 1.8 Ca 0.8 La 0.3 Cu 2.1 O 8+δ are discussed. Delayed absorption onsets attributed to giant resonances (Ba 4d→4f, La 4d→4f, and Nd 4d→4f transitions) are also reported

  10. Synthesis, structure and magnetic behavior of a new three-dimensional Manganese phosphite-oxalate: [C2N2H10][Mn2II(OH2)2(HPO3)2(C2O4)

    International Nuclear Information System (INIS)

    Ramaswamy, Padmini; Mandal, Sukhendu; Natarajan, Srinivasan

    2009-01-01

    A novel manganese phosphite-oxalate, [C 2 N 2 H 10 ][Mn 2 II (OH 2 ) 2 (HPO 3 ) 2 (C 2 O 4 )] has been hydothermally synthesized and its structure determined by single-crystal X-ray diffraction. The structure consists of neutral manganese phosphite layers, [Mn(HPO 3 )] ∞ , formed by MnO 6 octahedra and HPO 3 units, cross-linked by the oxalate moieties. The organic cations occupy the middle of the 8-membered one-dimensional channels. Magnetic studies indicate weak antiferromagnetic interactions between the Mn 2+ ions. - Abstract: A new antiferromagnetic three-dimensional inorganic-organic hybrid compound, [C 2 N 2 H 10 ][Mn 2 II (OH 2 ) 2 (HPO 3 ) 2 (C 2 O 4 )] has been prepared hydrothermally. The compound has neutral manganese layers pillared by oxalate units. The neutral manganese layers are shown here. Display Omitted

  11. Bis(μ-2-methylquinolin-8-olato-κ3N,O:O;κ3O:N,O-bis[(methanol-κO(nitrato-κ2O,O′lead(II

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available The molecule of the title compound, [Pb2(C10H8NO2(NO32(CH3OH2], lies about a centre of inversion. The Pb atom is chelated by nitrate and substituted quinolin-8-olate anions. The O atom of the quinolin-8-olate also bridges, to confer a six-coordinate status on the metal centre. When a longer Pb...O interaction is considered, the geometry approximates a Ψ-cube in which one of the sites is occupied by a stereochemically active lone pair.

  12. A better ferrimagnetic half-metal LuCu{sub 3}Mn{sub 4}O{sub 12}: Predicted from first-principles investigation

    Energy Technology Data Exchange (ETDEWEB)

    Lv Shuhui; Li Hongping [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School, Chinese Academy of Sciences, Beijing 100049 (China); Han Deming; Wu Zhijian [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Liu Xiaojuan, E-mail: lxjuan@ciac.jl.c [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Meng Jian, E-mail: jmeng@ciac.jl.c [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2011-03-15

    Electronic structure calculations based on density functional theory (DFT) within the generalized gradient approximation (GGA) and GGA+U for manganite cuprate compound LuCu{sub 3}Mn{sub 4}O{sub 12} have been performed, using the full-potential linearized augmented plane wave method. The calculated results indicate that LuCu{sub 3}Mn{sub 4}O{sub 12} is ferrimagnetic and half-metallic in both GGA and GGA+U calculations. The minority-spin band gap is 0.7 eV within GGA, which is larger than that of LaCu{sub 3}Mn{sub 4}O{sub 12} (0.3 eV), indicating its better half-metallicity. Further, the minority-spin gap enlarges from 0.7 to 2.8 eV with U taken into account, and simultaneously the Fermi level being shifted to the middle of the gap, making the half-metallic energy gap to be 1.21 eV. These results demonstrate that electronic correlation effect enhances the stability of half-metallic property. These facts make this system interesting candidates for applications in spintronic devices. - Research highlights: The electronic and magnetic properties of LuCu{sub 3}Mn{sub 4}O{sub 12} are analyzed. Both GGA and GGA+U methods are reported and compared. A better half-metal LuCu{sub 3}Mn{sub 4}O{sub 12} is obtained with large half-metallic gap. The results agree very well with the experimental data.

  13. Ag doped (Bi1.6Pb0.4Sr2CaCu2O8+δ textured rods

    Directory of Open Access Journals (Sweden)

    Díez, J. C.

    2008-06-01

    Full Text Available In this work, superconducting samples of (Bi1.6Pb0.4Sr2CaCu2O8+δ with Ag additions have been studied. (Bi1.6Pb0.4Sr2CaCu2O8+δ + x wt.% Ag (with x = 0, 1 and 3 powders were synthesized using a sol-gel method. The obtained powders were used as precursors to fabricate long textured cylindrical bars through a floating zone melting method. A drastic change on the microstructure has been found when comparing with undoped Bi2Sr2CaCu2O8+δ samples. The results showed that electrical resistivity at room temperature, critical current as well as flexural strength are improved when Ag is added to these Pb doped samples, while critical temperature does not change. On the other hand, it has been found that samples with composition (Bi1.6Pb0.4Sr2CaCu2O8+δ + Ag shown E-I curves with very high sharpness values on the zone of the superconducting to normal transition, reaching n-values (E∼In as high as 45 at 65K.Se han preparado polvos cerámicos de composición (Bi1.6Pb0.4Sr2CaCu2O8+δ + x % Ag en peso (con x = 0, 1 y 3 mediante un proceso sol-gel. Estos polvos se han utilizado para fabricar precursores que se texturaron por medio del método de fusión zonal flotante. Se ha encontrado un gran cambio en la microestructura cuando se compara con muestras de composición pura Bi2Sr2CaCu2O8+δ. Tanto la resistividad eléctrica a temperatura ambiente, como la corriente crítica, así como la resistencia a flexión se mejoran cuando la Ag se adiciona a estas muestras dopadas con Pb, mientras que no se observa cambio en la temperatura crítica. Por otra parte, se ha encontrado que las muestras de composición (Bi1.6Pb0.4Sr2CaCu2O8+δ + Ag presentan una gran pendiente de la curva E-I en la zona de transición entre el estado superconductor y el estado normal. Con estas composiciones, se han encontrado valores de n (E∼In de hasta 45 a 65K.

  14. NMR study of the molecular nanomagnet [Fe8(N3C6H15)6O2(OH)12]·[Br8·9H2O] in the high-spin magnetic ground state

    International Nuclear Information System (INIS)

    Furukawa, Y.; Kumagai, K.; Lascialfari, A.; Aldrovandi, S.; Borsa, F.; Sessoli, R.; Gatteschi, D.

    2001-01-01

    The magnetic molecular cluster [Fe 8 (N 3 C 6 H 15 ) 6 O 2 (OH) 12 ] 8+ [Br 8 ·9H 2 O] 8- , in short Fe8, has been investigated at low temperature by 1 H-NMR and relaxation measurements. Some measurements of 2 D-NMR in partially deuterated Fe8 clusters will also be reported. Upon decreasing temperature the NMR spectra display a very broad and structured signal which is the result of the internal local fields at the proton sites due to the local moments of the Fe(III) ions in the total S=10 magnetic ground state. The proton and deuteron NMR spectra have been analyzed and the different resonance peaks have been attributed to the different proton groups in the molecule. The simulation of the spectra by using a dipolar hyperfine field and the accepted model for the orientation of the Fe(III) local moments do not agree with the experiments even when the magnitude of the local Fe(III) moments is allowed to vary. It is concluded that a positive contact hyperfine interaction of the same order of magnitude as the dipolar interaction is present for all proton sites except the water molecules. The temperature and magnetic field dependence of the nuclear spin-lattice relaxation rate is ascribed to the fluctuations of the local Fe(III) moments, which follow rigidly the fluctuations of the total ground state magnetization of the nanomagnet. By using a simple model already utilized for the Mn12 cluster, we derive the value of the spin phonon coupling constant which determines the lifetime broadening of the different magnetic quantum number m substates of the S=10 ground state. It is shown that the lifetime broadening decreases rapidly on lowering the temperature. When the lifetime becomes longer than the reciprocal of the frequency shift of the proton lines a structure emerges in the NMR spectrum reflecting the ''frozen'' local moment configuration

  15. 1,8-Dihydroxy-2,4,5,7-tetranitro-9,10-anthraquinone

    Directory of Open Access Journals (Sweden)

    Mahsa Armaghan

    2010-05-01

    Full Text Available The ring system in the title compound, C14H4N4O12, is essentially planar (r.m.s. deviation of the carbon atoms = 0.085 Å; the two hydroxy groups form intramolecular hydrogen bonds to the same carbonyl O atom. The nitro groups are twisted with respect to the mean plane of the ring system by 74.3 (1 (1-nitro, 42.3 (3 (3-nitro, 45.7 (3 (6-nitro and 66.9 (1° (8-nitro.

  16. Electrochemical performance of co-doped Li1.2Mn0.6Ni0.2O2 cathode materials

    CSIR Research Space (South Africa)

    David, K

    2013-04-01

    Full Text Available The composite material has a xLi2MnO3·(1-x)LiMO2 (M = Mn, Co, Ni) structure has been considered as one of the most promising cathode materials for advanced lithium-ion batteries due to their low-cost and high capacity (> 200 mAh g−1) between 4.8 V...

  17. Highly efficient alkane oxidation catalyzed by [Mn(V)(N)(CN)4](2-). Evidence for [Mn(VII)(N)(O)(CN)4](2-) as an active intermediate.

    Science.gov (United States)

    Ma, Li; Pan, Yi; Man, Wai-Lun; Kwong, Hoi-Ki; Lam, William W Y; Chen, Gui; Lau, Kai-Chung; Lau, Tai-Chu

    2014-05-28

    The oxidation of various alkanes catalyzed by [Mn(V)(N)(CN)4](2-) using various terminal oxidants at room temperature has been investigated. Excellent yields of alcohols and ketones (>95%) are obtained using H2O2 as oxidant and CF3CH2OH as solvent. Good yields (>80%) are also obtained using (NH4)2[Ce(NO3)6] in CF3CH2OH/H2O. Kinetic isotope effects (KIEs) are determined by using an equimolar mixture of cyclohexane (c-C6H12) and cyclohexane-d12 (c-C6D12) as substrate. The KIEs are 3.1 ± 0.3 and 3.6 ± 0.2 for oxidation by H2O2 and Ce(IV), respectively. On the other hand, the rate constants for the formation of products using c-C6H12 or c-C6D12 as single substrate are the same. These results are consistent with initial rate-limiting formation of an active intermediate between [Mn(N)(CN)4](2-) and H2O2 or Ce(IV), followed by H-atom abstraction from cyclohexane by the active intermediate. When PhCH2C(CH3)2OOH (MPPH) is used as oxidant for the oxidation of c-C6H12, the major products are c-C6H11OH, c-C6H10O, and PhCH2C(CH3)2OH (MPPOH), suggesting heterolytic cleavage of MPPH to generate a Mn═O intermediate. In the reaction of H2O2 with [Mn(N)(CN)4](2-) in CF3CH2OH, a peak at m/z 628.1 was observed in the electrospray ionization mass spectrometry, which is assigned to the solvated manganese nitrido oxo species, (PPh4)[Mn(N)(O)(CN)4](-)·CF3CH2OH. On the basis of the experimental results the proposed mechanism for catalytic alkane oxidation by [Mn(V)(N)(CN)4](2-)/ROOH involves initial rate-limiting O-atom transfer from ROOH to [Mn(N)(CN)4](2-) to generate a manganese(VII) nitrido oxo active species, [Mn(VII)(N)(O)(CN)4](2-), which then oxidizes alkanes (R'H) via a H-atom abstraction/O-rebound mechanism. The proposed mechanism is also supported by density functional theory calculations.

  18. Preparation and melting of uranium from U3O8

    International Nuclear Information System (INIS)

    Hur, Jin-Mok; Choi, In-Kyu; Cho, Soo-Haeng; Jeong, Sang-Mun; Seo, Chung-Seok

    2008-01-01

    In this paper, we report on the preparation and melting of uranium in association with a spent nuclear fuel conditioning process. U 3 O 8 powder was electrochemically reduced in a mixture of molten LiCl-Li 2 O (∼3 wt.% of Li 2 O in LiCl) at 650 deg. C resulting in the formation of uranium and Li 2 O with a yield of >99%. When the powder of uranium with a residual LiCl-Li 2 O salt was heated in order to melt the metal, the uranium oxidation to UO 2 due to the reaction with Li 2 O was observed. We were able to synthesize FeU 6 by using a Fe based cathode during the U 3 O 8 reduction procedure. FeU 6 could be melted to below the temperatures where the oxidation of uranium by Li 2 O occurred. The idea of compound formation and melting is applicable to the melting and casting of a spent nuclear fuel which contains oxidative residual salts due to its conditioning in a molten salt

  19. Synthesis, crystal structure and electrical properties of A-site cation ordered BaErMn2O5 and BaErMn2O6

    International Nuclear Information System (INIS)

    Świerczek, Konrad; Klimkowicz, Alicja; Zheng, Kun; Dabrowski, Bogdan

    2013-01-01

    In this paper, we report on a synthesis procedure, structural and electrical properties of BaErMn 2 O 5 and BaErMn 2 O 6 , A-site double perovskites having layered arrangement of Ba and Er cations. These materials belong to a family of BaLnMn 2 O 5+δ oxides, which up to now were successfully synthesized for Ln=Y and La–Ho lanthanides. Up to our knowledge, this is the first report on the successful synthesis of BaErMn 2 O 5 and BaErMn 2 O 6 , yielding>95 wt% of the considered compounds. Structural characterization of the materials is given at room temperature, together with in situ XRD studies, performed during oxidation of BaErMn 2 O 5 in air, at elevated temperatures up to 500 °C. A complex structural behavior was observed, with oxidation process of BaErMn 2 O 5 occurring at around 300 °C. The oxidized BaErMn 2 O 6 shows a structural phase transition at about 225 °C. Results of structural studies are supported by thermogravimetric measurements of the oxidation process, performed in air, as well as reduction process, preformed in 5 vol% of H 2 in Ar. Additionally, isothermal oxidation/reduction cycles were measured at 500 °C, showing interesting properties of BaErMn 2 O 5+δ , from a point of view of oxygen storage technology. Electrical conductivity of BaErMn 2 O 5 is of the order of 10 −4 S cm −1 at room temperature and shows activated character on temperature with activation energy E a =0.30(1) eV. Positive sign of Seebeck coefficient for this material indicates holes as dominant charge carriers. Oxidized BaErMn 2 O 6 possesses much higher electrical conductivity, almost 0.2 S cm −1 at room temperature. Additional, about 10-fold increase of electrical conductivity, occurring in the vicinity of 225 °C for this material, can be associated with phase transition from charge/orbital-ordered insulator COI(CE) to paramagnetic metal PM phase. The highest conductivity for BaErMn 2 O 6 was measured near 500 °C and is almost equal to 40 S cm −1 , while

  20. 2,2,3,3,5,5,6,6-Octa-p-tolyl-1,4-dioxa-2,3,5,6-tetragermacyclohexane dichloromethane disolvate

    Directory of Open Access Journals (Sweden)

    Monika L. Amadoruge

    2009-09-01

    Full Text Available The title compound, C56H56Ge4O2·2CH2Cl2 or Tol8Ge4O2·2CH2Cl2 (Tol = p-CH3C6H4, was obtained serendipitously during the attempted synthesis of a branched oligogermane from Tol3GeNMe2 and PhGeH3. The molecule contains an inversion center in the middle of the Ge4O2 ring which is in a chair conformation. The Ge—Ge bond distance is 2.4418 (5 Å and the Ge—O bond distances are 1.790 (2 and 1.785 (2 Å. The torsion angles within the Ge4O2 ring are −56.7 (1 and 56.1 (1° for the Ge—Ge—O—Ge angles and −43.9 (1° for the O—Ge—Ge—O angle.

  1. Synthesis of Li-Mn-O mesocrystals with controlled crystal phases through topotactic transformation of MnCO3

    Science.gov (United States)

    Dang, Feng; Hoshino, Tatsuhiko; Oaki, Yuya; Hosono, Eiji; Zhou, Haoshen; Imai, Hiroaki

    2013-02-01

    Mesocrystals of Li-Mn-O compounds, such as LiMn2O4, Li2MnO3, and LiMnO2-Li2MnO3, consisting of oriented nanoscale units were selectively produced under hydrothermal conditions from biomimetically prepared MnCO3 mesocrystals. Topotactic transformation through the intermediate phase of Mn5O8 inheriting a hierarchical structure of the MnCO3 precursor was essential for the formation of the mesocrystal compounds. The crystal phases were successfully controlled by varying the conditions for the hydrothermal reactions. The Li-Mn-O mesocrystals have considerable potential as cathodes of Li-ion batteries.Mesocrystals of Li-Mn-O compounds, such as LiMn2O4, Li2MnO3, and LiMnO2-Li2MnO3, consisting of oriented nanoscale units were selectively produced under hydrothermal conditions from biomimetically prepared MnCO3 mesocrystals. Topotactic transformation through the intermediate phase of Mn5O8 inheriting a hierarchical structure of the MnCO3 precursor was essential for the formation of the mesocrystal compounds. The crystal phases were successfully controlled by varying the conditions for the hydrothermal reactions. The Li-Mn-O mesocrystals have considerable potential as cathodes of Li-ion batteries. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr33767g

  2. Modulation-free bismuth-lead cuprate superconductors: BiPbSr1+xL1-xCuO6 and BiPbSr2Y1-xCaxCu2O8

    International Nuclear Information System (INIS)

    Manivannan, V.; Gopalakrishnan, J.; Rao, C.N.R.

    1991-01-01

    Modulation-free BiPbSrLCuO 6 (L=La, Pr, Nd) and BiPbSr 2 YCu 2 O 8 , which are isotypic with the n=1 and 2 members of the Bi 2 Sr 2 Ca n-1 Cu n O 2n+4 family, have been prepared and characterized. These parent compounds are nonsuperconducting, but when doped with holes by substitution chemistry give modulation-free superconducting cuprates of the general formulas BiPbSr 1+xL1-x CuO 6 and BiPbSr 2 Y 1-x Ca x Cu 2 O 8 , exhibiting maximum T c 's of 24 and 85 K, respectively. Significantly, the hole concentration at the maximum T c is 0.12 in the cuprate family with a single Cu-O layer and 0.22 in that with two Cu-O layers

  3. Raman spectroscopic study of the minerals apophyllite-(KF) KCa4Si8O20F·8H2O and apophyllite-(KOH) KCa4Si8O20(F,OH)·8H2O

    Science.gov (United States)

    Frost, Ray L.; Xi, Yunfei

    2012-11-01

    Raman spectroscopy complimented with infrared spectroscopy has been used to study the variation in molecular structure of two minerals of the apophyllite mineral group, namely apophyllite-(KF) KCa4Si8O20F·8H2O and apophyllite-(KOH) KCa4Si8O20(F,OH)·8H2O. apophyllite-(KF) and apophyllite-(KOH) are different minerals only because of the difference in the percentage of fluorine to hydroxyl ions. The Raman spectra are dominated by a very intense sharp peak at 1059 cm-1. A band at around 846 cm-1 is assigned to the water librational mode. It is proposed that the difference between apophyllite-(KF) and apophyllite-(KOH) is the observation of two Raman bands in the OH stretching region at around 3563 and 3625 cm-1. Multiple water stretching and bending modes are observed showing that there is much variation in hydrogen bonding between water and the silicate surfaces.

  4. The quaternary arsenide oxides Ce{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} and Pr{sub 9}Au{sub 5-x}As{sub 8}O{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, Timo; Hoffmann, Rolf-Dieter; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie

    2016-07-01

    The quaternary gold arsenide oxides Ce{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} and Pr{sub 9}Au{sub 5-x}As{sub 8}O{sub 6} were synthesized from the rare earth elements (RE), rare earth oxides, arsenic and gold powder at maximum annealing temperatures of 1173 K. The structures were refined from single crystal X-ray diffractometer data: Pnnm, a=1321.64(6) pm, b=4073.0(3), c=423.96(2), wR2=0.0842, 3106 F{sup 2} values, 160 variables for Ce{sub 9}Au{sub 4.91(4)}As{sub 8}O{sub 6} and Pnnm, a=1315.01(4), b=4052.87(8), c=420.68(1) pm, wR2=0.0865, 5313 F{sup 2} values, 160 variables for Pr{sub 9}Au{sub 4.75(1)}As{sub 8}O{sub 6}. They represent a new structure type and show a further extension of pnictide oxide crystal chemistry. A complex polyanionic gold arsenide network [Au{sub 5}As{sub 8}]{sup 15-} (with some disorder in the gold substructure) is charge compensated with polycationic strands of condensed edge-sharing O rate at RE{sub 4/4} and O rate at RE{sub 4/3} tetrahedra ([RE{sub 4}O{sub 3}]{sub 2}{sup 12+}) as well as RE{sup 3+} cations in cavities.

  5. Ethyl 13-(4-chlorophenyl-11-methyl-6-oxo-5-phenyl-8-thia-3,4,5,10-tetraazatricyclo[7.4.0.02,7]trideca-1(9,2(7,3,10,12-pentaene-12-carboxylate

    Directory of Open Access Journals (Sweden)

    Elham A. Al-Taifi

    2016-05-01

    Full Text Available In the title molecule, C24H17ClN4O3S, the central tricyclic moiety is twisted slightly, as indicated by the dihedral angles of 4.86 (5 and 0.97 (6°, respectively, between the five-membered ring and the C3N3 and pyridyl rings. Additionally, the chlorobenzene ring makes a dihedral angle of 65.80 (5° with the pyridyl ring. Weak C—H...O, C—Cl...N [3.0239 (13 Å] and π–π stacking interactions [inter-centroid distance between thienyl rings = 3.6994 (8 Å, and between thienyl and pyridyl rings = 3.7074 (8 Å] contribute to the molecular packing. The ethyl group in the ester moiety is disordered over two sets of sites, with the major component having an occupancy of 0.567 (11.

  6. Phase transition in Sr8[Al12O24](MoO4)2 aluminate sodalite (SAM)

    International Nuclear Information System (INIS)

    Depmeier, W.; Melzer, R.; Hu, X.

    1993-01-01

    The cubic-tetragonal phase transition at 571 K of the aluminate sodalite Sr 8 [Al 12 O 24 ](MoO 4 ) 2 (SAM) has ben studied by following the position of the (pseudo-)cubic {400} reflections as a function of temperature. The high resolution of the synchrotron powder diffraction experiment allowed the temperature dependencies to be followed with good precision. The tetragonal a lattice parameter appears to be a linear extrapolation of the cubic one, with only a small upward shift at the transition, whereas the c parameter decreases strongly below 571 K. These observations can be explained by a model which assumes the superposition of a ferroelastic strain component, and a volume strain component. The volume strain can be rationalized as being the result of a 'shearing' of the sodalite framework. Causes and consequences of the 'shearing' in relation to the sodalite framework are discussed. The weakly first-order transition is nearly tricritical; power-law exponents seem to be influenced by defects. The thermal expansion of the cubic lattice parameter, as well as of the tetragonal a axis, is nearly linear. The linear thermal-expansion coefficient α is 8.6(4)x10 -6 K -1 . The tetragonal c axis also expands linearly between room temperature and about Tc-100 K with practically the same coefficient, but behaves non-linearly nearer to the transition temperature. (orig.)

  7. Multiferroic magnetoelectric coupling effect of bilayer La1.2Sr1.8Mn2O7/PbZr0.3Ti0.7O3 complex thin film

    Science.gov (United States)

    Liang, K.; Zhou, P.; Ma, Z. J.; Qi, Y. J.; Mei, Z. H.; Zhang, T. J.

    2017-05-01

    Magnetoelectric (ME) coupling effect of 2-2-type ferromagnetic/ferroelectric bi-layer multiferroic epitaxial thin film (La1.2Sr1.8Mn2O7/PbZr0.3Ti0.7O3, LSMO/PZT) on SrRuO3 (SRO) substrate is investigated systematically by using Landau-Ginzburg-Devonshire (LGD) thermodynamic theory and modified constitutive equations. The calculating results clarify the detail relationships between ME coupling response and the residual strain, the volume fraction of constituent phases, the interface coupling coefficients, the magnetic field and the temperature. It also shows that improved ME coupling response can be modulated by these parameters. External magnetic fields (H1) induced ME coupling effect could be enhanced around Curie Temperature (Tc) of ferromagnetic phase and ME voltage coefficient (αE31) approaches a maximum at H1 ∼ 4.5 kOe near Tc. The remarkable variations of ME coupling response can be used to provide useful guidelines on the design of multifunctional devices.

  8. A hierarchical nanostructure consisting of amorphous MnO{sub 2}, Mn{sub 3}O{sub 4} nanocrystallites, and single-crystalline MnOOH nanowires for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Chi-Chang; Hung, Ching-Yun [Department of Chemical Engineering, National Tsing Hua University, Hsin-Chu 30013 (China); Chang, Kuo-Hsin [Department of Chemical Engineering, National Tsing Hua University, Hsin-Chu 30013 (China); Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621 (China); Yang, Yi-Lin [Department of Chemical Engineering, National Chung Cheng University, Chia-Yi 621 (China)

    2011-01-15

    In this communication, a porous hierarchical nanostructure consisting of amorphous MnO{sub 2} (a-MnO{sub 2}), Mn{sub 3}O{sub 4} nanocrystals, and single-crystalline MnOOH nanowires is designed for the supercapacitor application, which is prepared by a simple two-step electrochemical deposition process. Because of the gradual co-transformation of Mn{sub 3}O{sub 4} nanocrystals and a-MnO{sub 2} nanorods into an amorphous manganese oxide, the cycle stability of a-MnO{sub 2} is obviously enhanced by adding Mn{sub 3}O{sub 4}. This unique ternary oxide nanocomposite with 100-cycle CV activation exhibits excellent capacitive performances, i.e., excellent reversibility, high specific capacitances (470 F g{sup -1} in CaCl{sub 2}), high power property, and outstanding cycle stability. The highly porous microstructures of this composite before and after the 10,000-cycle CV test are examined by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). (author)

  9. Propane-1,3-diaminium–2-carboxypyridine-6-carboxylate–pyridine-2,6-dicarboxylic acid–water (1/2/2/8

    Directory of Open Access Journals (Sweden)

    Hossein Aghabozorg

    2008-01-01

    Full Text Available The title proton-transfer compound, C3H12N22+·2C7H4NO4−·2C7H5NO4·8H2O or (pnH2(pydcH2.2(pydcH2·8H2O, was obtained by the reaction of pyridine-2,6-dicarboxylic acid (pydcH2 and propane-1,3-diamine (pn in aqueous solution. Both neutral and monoanionic forms of the diacid are observed in the crystal structure. The negative charge of two monoanions is balanced by the dicationic propane-1,3-diaminium species. In addition, considerable π–π stacking interactions between the aromatic rings of the (pydcH− and (pydcH2 fragments [with centroid–centroid distances of 3.5108 (11–3.5949 (11 Å] are observed. The most important feature of this crystal structure is the presence of a large number of O—H...O, O—H...N, N—H...O, N—H...N, C—H...O and C—H...N hydrogen bonds, with D...A ranging from 2.445 (2 to 3.485 (3 Å. These interactions as well as ion pairing and π–π stacking connect the various fragments into a supramolecular structure.

  10. Bis(2-methoxybenzylammonium diaquabis(dihydrogen diphosphato-κ2O,O′manganate(II dihydrate

    Directory of Open Access Journals (Sweden)

    Adel Elboulali

    2013-11-01

    Full Text Available The asymmetric unit of the title compound, (C8H12NO2[Mn(H2P2O72(H2O22H2O, consists of half an MnII complex anion, a 2-methoxybenylammonium cation and a solvent water molecule. The MnII complex anion lies across an inversion center, and has a slightly distorted octahedral coordination environment for the MnII ion, formed by two bidentate dihydrogendiphosphate ligands and two water molecules. In the crystal, the components are linked by O—H...O and N—H...O hydrogen bonds, forming layers parallel to (100. An intramolecular N—H...O hydrogen bond is also observed.

  11. Interaction in the NaIn(MoO4)2 - AMoO4 (A = Mg, Mn) systems

    International Nuclear Information System (INIS)

    Kotova, I.Yu.; Kozhevnikova, N.M.

    2001-01-01

    The results of investigation into NaIn(MoO 4 ) 2 - AMoO 4 (A = Mg, Mn) quasibinary cross-sections by means of X-ray diffraction and differential thermal analysis are presented. Conducted researches revealed that compounds NaMg 3 In(MoO 4 ) and NaMn 3 In(MoO 4 ) melting incongruently at 990 Deg C and 940 Deg C accordingly were formed in the NaIn(MoO 4 ) - AMoO 4 (A = Mg, Mn) systems. The data of initiation of X-ray diffraction pattern of NaMg 3 In(MoO 4 ) 5 are presented. The temperature dependences of conductivity, dielectric permeability and tangent of dielectric losses indicative on ionic-electronic nature conductivity are determined. Activation energy of conductivity in the Mg - Mn row changes moderately - from 9.91 till 5.71 eV [ru

  12. K{sub 2}MnF{sub 5}·H{sub 2}O as reactant for synthesizing highly efficient red emitting K{sub 2}TiF{sub 6}:Mn{sup 4+} phosphors by a modified cation exchange approach

    Energy Technology Data Exchange (ETDEWEB)

    Han, Tao, E-mail: danbaiht@126.com; Wang, Jun; Lang, Tianchun; Tu, Mingjing; Peng, Lingling

    2016-11-01

    As reactant for synthesizing K{sub 2}TiF{sub 6}:Mn{sup 4+} phosphors, the cross-shaped and cuboid-shaped K{sub 2}MnF{sub 5}·H{sub 2}O powders were prepared by the simple chemical method. Based on the reaction mechanism, oxidizing K{sub 2}MnF{sub 5}·H{sub 2}O (Mn{sup 3+}) to Mn{sup 4+} by KMnO{sub 4} (Mn{sup 7+}), a modified cation exchange approach for synthesizing highly efficient red emitting K{sub 2}TiF{sub 6}:Mn{sup 4+} phosphor was proposed. The obtained K{sub 2}TiF{sub 6}:Mn{sup 4+} (2.7–5.3 at.%) phosphors have the size of 30–80 μm with a rough surface, their emission spectra consist of five narrow bands extending from 580 to 660 nm with the strongest peak at 634.8 nm, whose relative emitting intensity depends on the molar ratio of KMnO{sub 4} to K{sub 2}MnF{sub 5}·H{sub 2}O (the platform value = 3.2), and two broad excitation bands are peaking at ∼365 nm and ∼460 nm. The internal quantum yield of our synthesized K{sub 2}TiF{sub 6}:Mn{sup 4+} phosphors is up to 82.5%, which is higher than the commercial CaAlSiN{sub 3}:Eu{sup 2+} value, their excitation bands peak at ∼460 and ∼365 nm are consistent with those of Y{sub 3}A{sub 5}O{sub 12}:Ce{sup 3+} phosphors and their emission bands are more suitable for the sensitivity curve of photopic human vision. In addition, our synthesized phosphors show better thermal quenching properties. These findings show a large potential of the synthesized K{sub 2}TiF{sub 6}:Mn{sup 4+} phosphors for commercialization. - Highlights: • We synthesize the cross-shaped and cuboid-shaped K{sub 2}MnF{sub 5}·H{sub 2}O. • K{sub 2}MnF{sub 5}·H{sub 2}O is as a reactant for synthesizing K{sub 2}TiF{sub 6}:Mn{sup 4+} phosphors. • K{sub 2}TiF{sub 6}:Mn{sup 4+} will improve the current white LED with high CRI for indoor lighting.

  13. The oxidation of ReCl_5 with oleum: synthesis and crystal structure of Re_2O_4Cl_4(SO_4)

    International Nuclear Information System (INIS)

    Betke, Ulf; Wickleder, Mathias S.

    2012-01-01

    The reaction of ReCl_5 and fuming sulfuric acid (25 % SO_3) in a sealed glass tube at 200 C led to red, needle shaped single crystals of Re_2O_4Cl_4(SO_4) (monoclinic, C2/c, a = 1501.8(2) pm, b = 1545.9(2) pm, c = 945.18(8) pm, β = 98.761(9) , Z = 8). In the crystal structure the [ReO_2] moieties are linked by [SO_4]"2"- tetrahedra to chains along the [101] direction. Each sulfate ion connects four rhenium atoms, additional two chloride ions complete the octahedral coordination sphere of each rhenium atom according to "1_∞[ReO_2_/_1Cl_2_/_1(SO_4)_2_/_4]. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. The synthesis of 8-β-[(methylsulfinyl-[18O])-methyl]-6-propylergoline

    International Nuclear Information System (INIS)

    Wheeler, W.J.

    1987-01-01

    The synthesis of 18 O-labeled 8-Β-[(methylsulfinyl)-methyl]-6-propyl-ergoline(pergolide-[ 18 O]-sulfoxide) of undetermined stereochemistry by the reaction of 8-Β-(methylthiomethyl)-6-propyl-ergoline (pergolide) with bis-(4-methoxyphenyl)-selen-[ 18 O]-oxide in acetic acid is described. Although the yields were low and the incorporation of 18 O was not high, this procedure represents a convenient method for the preparation of 18 O-labeled sulfoxides of pergolide and other sulfides present in compounds for which the usual methods are inappropriate. (author)

  15. Investigation of the magnetic structure of KFeCl3, KFeBr3, Rb2MnCl4, and Rb3Mn2Cl7 compounds with magnetic correlations in one and two dimensions

    International Nuclear Information System (INIS)

    Gurewitz, E.

    1976-12-01

    The crystallographic structure of KFeCl 3 and KFeBr 3 consists of (FeCl) - octahedra packed in isolated zigzagging chains. These compounds order antiferromagnetically at Tsub(N) approximately 16 deg K and Tsub(N) approximately 9.5 deg K, respectively. Below Tsub(N) the Fe 2+ magnetic moments within a chain are ferromagnetically coupled, parallel to the chain axis, while the chains are coupled antiferromagnetically. In the temperatures Tsub(N) 3 has magnetic correlations within the chains only, whereas the correlations between the chains are negligible. Moessbauer effect measurements at these temperatures show a distinct hyperfine magnetic splitting, characteristic of relaxation phenomena. Cs 2 MnCl 4 , Rb 2 MnCl 4 and Rb 3 Mn 2 Cl 7 belong to the Asub(n+1)Bsub(n)Xsub(3n+1) family of compounds, with the Dsub(4h)sup(17) space group. These compounds order antiferromagnetically at Tsub(N) approximately 55 deg K for Cs 2 MnCl 4 and Rb 2 MnCl 4 , and Tsub(N) approximately 64.5 deg K for Rb 3 Mn 2 Cl 7 . Below Tsub(N) each Mn 2+ moment is along the c-axis and is coupled antiferromagnetically to the moments of its nearest neighbours (nn). These compounds behave like a two-dimensional antiferromagnet at T >= Tsub(N). Neutron scans of the reciprocal space exhibit rods of reflections along c vectorsup(*). The negligible interactions between next nn sets of MnCl 2 layers, a distance c vector apart, yield both in Rb 2 MnCl 4 and in Rb 3 Mn 2 Cl 7 , two distinctive magnetic structures (polytypes) below Tsub(N). (author)

  16. Bis(μ-2-carboxymethyl-2-hydroxybutanedioatobis[diaquamanganese(II]–1,2-bis(pyridin-4-ylethene–water (1/1/2

    Directory of Open Access Journals (Sweden)

    In Hong Hwang

    2012-12-01

    Full Text Available The asymmetric unit of the title compound, [Mn2(C6H6O72(H2O4]·C12H10N2·2H2O, contains half of the centrosymmetric Mn complex dimer, half of a 1,2-bis(pyridin-4-ylethene molecule, which lies across an inversion center, and one water molecule. Two citrate ligands bridge two MnII ions, and each MnII atom is coordinated by four O atoms from the citrate ligands (one from hydroxy and three from carboxylate groups and two water O atoms, forming a distorted octahedral environment. In the crystal, O—H...O and O—H...N hydrogen bonds link the centrosymmetric dimers and lattice water molecules into a three-dimensional structure which is further stabilized by intermolecular π–π interactions [centroid–centroid distance = 3.959 (2 Å]. Weak C—H...O hydrogen bonding interactions are also observed.

  17. Solid-phase reduction of silico-12-molybdic acid H4SiMo12O40 by some organic oxygen containing compounds

    International Nuclear Information System (INIS)

    Chuvaev, V.F.; Pinchuk, I.N.; Spitsyn, V.I.

    1982-01-01

    A study is made on reduction reactions of anhydrous silico-12-molybdic acid by vapors of organic oxygen-containing compounds at 170 deg C: alcohols, simple carbonyl compounds. Methods of thermal analysis, electron paramagnetic resonance, paramagnetic resonance were used to established that depending on the nature of organic reagent and temperature, H 6 SiMo 2 5 Mo 10 6 O 40 two-electron or H 8 SiMo 4 5 Mo 8 6 O 40 four-electron flues form. It is shown that the increase of heterogeneous reduction temperature can lead to formation of anhydrous phases of SiMo 12 O 38 -(n/2), able to attach water reversibly with formation of corresponding blue. Characteristics of blues, prepared during solid-phase reduction of silico-12-molybdic acid and mixed valent forms with corresponding reduction degree, separated from water solutions, were compared

  18. Ca8Mg(SiO4)4Cl2:Ce3+, Tb3+: A potential single-phased phosphor for white-light-emitting diodes

    International Nuclear Information System (INIS)

    Zhu Ge; Wang Yuhua; Ci Zhipeng; Liu Bitao; Shi Yurong; Xin Shuangyu

    2012-01-01

    A single-phased white-light-emitting phosphor Ca 8 Mg(SiO 4 ) 4 Cl 2 :Ce 3+ , Tb 3+ (CMSC:Ce 3+ , Tb 3+ ) is synthesized by a high temperature solid-state reaction method, and its photoluminescence properties are investigated. The obtained phosphor exhibits a strong excitation band between 250 and 410 nm, matching well with the dominant emission band of a UV light-emitting-diode (LED) chip. Energy transfer from Ce 3+ to Tb 3+ ions has been investigated and demonstrated to be a resonant type via a dipole–dipole mechanism. The energy transfer efficiency as well as the critical distance is also estimated. Furthermore, the phosphors can generate light from yellow-green through white and eventually to blue by properly tuning the relative ratio of Ce 3+ to Tb 3+ ions grounded on the principle of energy transfer. The results show that this phosphor has potential applications as a single-phased phosphor for UV white-light LEDs. - Highlights: ► The luminescence properties of Ca 8 Mg(SiO 4 ) 4 Cl 2 :Ce 3+ , Tb 3+ were investigated for the first time. ► The strong absorption of phosphors matches well with the emission band of UV LED chips. ► The energy transfer from Ce 3+ to Tb 3+ in Ca 8 Mg(SiO 4 ) 4 Cl 2 was investigated in detail. ► The white light (CIE=(0.29, 0.34)) is generated by tuning the relative ratio of Ce 3+ to Tb 3+ .

  19. Energy transfer in Pr3+ and Mn2+ co-doped SrB6O10 and SrB4O7

    International Nuclear Information System (INIS)

    Chen Yonghu; Yan Wuzhao; Shi Chaoshu

    2007-01-01

    The luminescent properties of Pr 3+ and Mn 2+ -doped SrB 6 O 10 and SrB 4 O 7 powder samples were investigated from the point of view of energy transfer between Pr 3+ and Mn 2+ . The emission from the 1 S 0 level of Pr 3+ was found in the SrB 6 O 10 :Pr 3+ sample as well as in the SrB 4 O 7 :Pr 3+ sample, indicating the 1 S 0 level is below the lowest 4f5d energy level in these hosts. The spectral overlaps between the emission spectra of Pr 3+ -doped samples and the excitation spectra of Mn 2+ -doped sample were found in both kinds of strontium borates. These spectral overlaps are in favor of the energy transfer from Pr 3+ to Mn 2+ . However, in the emission spectra of the SrB 6 O 10 :Pr 3+ , Mn 2+ , no indication of energy transfer was observed, though the emission spectra of SrB 4 O 7 :Pr 3+ , Mn 2+ did show evidence of energy transfer from Pr 3+ to Mn 2+ . The possible reasons were discussed

  20. Ethane-1,2-diaminium 4,5-dichlorophthalate

    Directory of Open Access Journals (Sweden)

    Graham Smith

    2010-01-01

    Full Text Available In the structure of the title compound, C2H10N22+·C8H2Cl2O42−, the dications and dianions form hydrogen-bonded ribbon substructures which enclose conjoint cyclic R21(7, R12(7 and R42(8 associations and extend down the c-axis direction. These ribbons inter-associate down b, giving a two-dimensional sheet structure. In the dianions, one of the carboxylate groups is essentially coplanar with the benzene ring, while the other is normal to it [C—C—C—O torsion angles = 177.67 (12 and 81.94 (17°, respectively].

  1. The LiyNi0.2Mn0.2Co0.6O2 electrode materials: A structural and magnetic study

    International Nuclear Information System (INIS)

    Labrini, Mohamed; Saadoune, Ismael; Almaggoussi, Abdelmajid; Elhaskouri, Jamal; Amoros, Pedro

    2012-01-01

    Graphical abstract: EPR signal of the Li 0.6 Co 0.6 Ni 0.2 Mn 0.2 O 2 composition showing that Mn 4+ ions are the solely paramagnetic ions in the structure. Highlights: ► LiCo 0.6 Ni 0.2 Mn 0.2 O 2 was prepared by the combustion method with sucrose as a fuel. ► Chemical delithiaition was performed by using NO 2 BF 4 oxidizing agent. ► The rhombohedral symmetry was preserved upon lithium removal. ► Lithium extraction leads to Ni 2+ oxidation to Ni 4+ followed by Co 3+ oxidation. ► The EPR narrow signal of Li 0.6 Co 0.6 Ni 0.2 Mn 0.2 O 2 is due to the only active Mn 4+ ions. -- Abstract: Layered LiNi 0.2 Mn 0.2 Co 0.6 O 2 phase, belonging to a solid solution between LiNi 1/2 Mn 1/2 O 2 and LiCoO 2 most commercialized cathodes, was prepared via the combustion method at 900 °C for a short time (1 h). Structural and magnetic properties of this material during chemical extraction were investigated. The powders adopted the α-NaFeO 2 structure with almost none of the well-known Li/Ni cation disorder. The analysis of the magnetic properties in the paramagnetic domain agrees with the combination of Ni 2+ (S = 1), Co 3+ (S = 0) and Mn 4+ (S = 3/2) spin-only values. X-ray analysis of the chemically delithiated Li y Ni 0.2 Mn 0.2 Co 0.6 O 2 reveals no structural transition. The process of lithium extraction from and insertion into LiNi 0.2 Mn 0.2 Co 0.6 O 2 was discussed on the basis of ex situ EPR experiments and magnetic susceptibility. Oxidation of Ni 2+ (S = 1) to Ni 3+ (S = 1/2) and to Ni 4+ (S = 0) was observed upon lithium removal.

  2. Thermal decomposition study of Mn doped Fe3O4 nanoparticles

    Science.gov (United States)

    Malek, Tasmira J.; Chaki, S. H.; Tailor, J. P.; Deshpande, M. P.

    2016-05-01

    Fe3O4 is an excellent magnetic material among iron oxides. It has a cubic inverse spinel structure exhibiting distinguished electric and magnetic properties. In this paper the authors report the synthesis of Mn doped Fe3O4 nanoparticles by wet chemical reduction technique at ambient temperature and its thermal characterization. Ferric chloride hexa-hydrate (FeCl3•6H2O), manganese chloride tetra-hydrate (MnCl24H2O) and sodium boro-hydrate (NaBH4) were used for synthesis of Fe3O4 nanoparticles at ambient temperature. The elemental composition of the as-synthesized Mn doped Fe3O4 nanoparticles were determined by energy dispersive analysis of X-rays (EDAX) technique. Thermogravimetric (TG) and differential thermal analysis (DTA) were carried out on the Mn doped Fe3O4 nanoparticles in the temperature range of ambient to 1124 K. The thermo-curves revealed that the particles decompose by four steps. The kinetic parameters were evaluated using non-mechanistic equations for the thermal decomposition.

  3. Synthesis, band structure, and optical properties of Ba2ZnV2O8

    International Nuclear Information System (INIS)

    Chen, D.-G.; Cheng, W.-D.; Wu, D.-S.; Zhang, H.; Zhang, Y.-C.; Gong, Y.-J.; Kan, Z.-G.

    2004-01-01

    A novel compound Ba 2 ZnV 2 O 8 has been synthesized in high temperature solution reaction and its crystal structure has been characterized by means of single crystal X-ray diffraction analysis. It crystallizes in monoclinic system and belongs to space group P2 1 /c with a=7.9050(16), b=16.149(3), c=6.1580(12)A, β=90.49(3). It builds up from 1-D branchy chains of [ZnV 2 O 8 4- ] ∞ , and the Ba 2+ cations are located in the space among these chains. The IR spectrum, ultraviolet-visible diffuse reflection integral spectrum and fluorescent spectra of this compound have been investigated. The calculated results of energy band structure by the density functional theory method show that the solid-state compound of Ba 2 ZnV 2 O 8 is an insulator with direct band gap of 3.48eV. The calculated total and partial density of states indicate that the top valence bands are contributions from the mixings of O-2p, V-3d, and Zn-3d states and low conduction bands mostly originate from unoccupied antibonding states between the V-3d and O-2p states. The V-O bonds are mostly covalence characters and Zn-O bonds are mostly ionic interactions, and the ionic interaction strength is stronger between the Ba-O than between the Zn-O. The refractive index of n x , n y , and n z is estimated to be 1.7453, 1.7469, and 1.7126, respectively, at wavelength of 1060nm for Ba 2 ZnV 2 O 8 crystal

  4. 1,1,2,2-Tetrakis[2,4-dichloro-6-(diethoxymethylphenoxymethyl]ethene

    Directory of Open Access Journals (Sweden)

    Yavuz Köysal

    2012-10-01

    Full Text Available In the title compound, C50H60Cl8O12, the molecules are disordered about an inversion center located at the mid-point of the central C=C bond. These atoms show disorder and were modelled with two different orientations with site occupancies of 0.828 (3 and 0.172 (3. The dihedral angle between the two benzene rings in the asymmetric unit is 52.80 (6°. Intramolecular C—H...O and C—H...Cl interactions occur and the crystal packing features inversion dimers linked by pairs of C—H...O bonds, generating R22(10 loops.

  5. Resistance switching mechanism of La_0_._8Sr_0_._2MnO_3_−_δ thin films

    International Nuclear Information System (INIS)

    Luo, X.D.; Gao, R.L.; Fu, C.L.; Cai, W.; Chen, G.; Deng, X.L.; Zhang, H.R; Sun, J.R.

    2016-01-01

    Effects of oxygen vacancies on the electrical transport properties of oxygen stoichiometric La_0_._8Sr_0_._2MnO_3 and oxygen-deficient La_0_._8Sr_0_._2MnO_3_−_δ films have been investigated. The result presents that the oxygen-deficient films annealed in vacuum show obvious increase of resistance and lattice parameter. With the sweeping voltage or temperature increasing, the resistance exhibits obvious bipolar switching effect, no forming process was needed. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Mn–O–Mn conduction channel due to the accumulation of oxygen vacancies under high external electric field or temperatures and hence is believed to be responsible for the bipolar resistance switching effect and the enhanced resistivity compared with oxygen stoichiometric La_0_._8Sr_0_._2MnO_3 film. These results may be important for practical applications in photoelectric or storage devices and point to a useful direction for other oxidizing materials.

  6. Crystal structure of 4,4′,4′′-(1,3,5-triazine-2,4,6-triyltripyridinium trichloride 2.5-hydrate

    Directory of Open Access Journals (Sweden)

    Bo-Kai Ling

    2015-11-01

    Full Text Available The asymmetric unit of the title compound, C18H15N63+·3Cl−·2.5H2O, contains two independent (1,3,5-triazine-2,4,6-triyltripyridinium cations. Both cations are approximately planar, the r.m.s. deviations of fitted non-H atoms being 0.045 and 0.051 Å. In the crystal, extensive O—H...Cl, O—H...O, N—H...Cl and N—H...O hydrogen bonds and weak C—H...Cl and C—H...O interactions link the organic cations, Cl− anions and water molecules into a three-dimensional supramolecular architecture. π–π stacking between the pyridine rings of adjacent cations is also observed, the centroid-to-centroid distance being 3.7578 (8 Å.

  7. Diaqua[(1R,2S,4R,8R,9S,11R-2,9-dimethyl-1,4,8,11-tetraazacyclotetradecane]nickel(II dichloride dihydrate

    Directory of Open Access Journals (Sweden)

    James Alan Townsend

    2012-08-01

    Full Text Available The crystal structure of the title complex, [Ni(C12H28N4(H2O2]Cl2·2H2O, displays O—H...Cl and O—H...O hydrogen bonding. The tetraazacyclotetradecane ligand interacts with the NiII atom in the cis V configuration and the final two ligand binding sites are occupied by water.

  8. Co-hydrothermal synthesis of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C nano-hybrid cathode material with enhanced electrochemical performance for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Jun; Luo, Shaohua; Chang, Longjiao; Hao, Aimin; Wang, Zhiyuan; Liu, Yanguo; Xu, Qian; Wang, Qing; Zhang, Yahui

    2017-01-01

    Highlights: • A co-hydrothermal approach to synthesize LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material in water/PEG system is present. • The Mn_1_-_xMg_xPO_4 precursor is prepared by precipitation reaction. • Co-modified with Mg"2"+ doping and LiAlO_2 compositing strategies play an important role in improving the electronic conductivity and facilitating the diffusion of lithium ion. • LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material exhibits a high specific discharge capacity of 151.8 mAh/g at 0.05C. - Abstract: LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C is synthesized by a co-hydrothermal method in water/PEG system using Li_2CO_3, AAO and Mn_1_-_xMg_xPO_4 as raw material. The electronic structure and micromorphology of multi-component compound LiMn_1_-_xMg_xPO_4/C (x = 0, 1/24, 1/12, 1/6) and nano-hybrid LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C cathode materials are studied by first-principles calculation and experimental research including XRD, SEM, TEM. The calculated band gap of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4/C is 2.296 eV, which is lower than other percentages Mg"2"+ doping samples. Electrochemical tests exhibit LiMn_2_3_/_2_4Mg_1_/_2_4PO_4/C has better cycling performance and rate capability than other contents Mg"2"+ doping samples with the discharge capacity of 143.5 mAh/g, 141.5 mAh/g, 139.2 mAh/g and 136.3 mAh/g at 0.05C, 0.1C, 0.5C and 1C in order. After compositing and preparation of LiMn_2_3_/_2_4Mg_1_/_2_4PO_4·LiAlO_2/C composite material by co-hydrothermal route, the initial discharge capacity reaches up to 151.8 mAh/g, which suggests that co-modified with Mg"2"+ doping and LiAlO_2 compositing material can improve the electronic conductivity of LiMnPO_4/C by facilitating the lithium ion diffusion rate in the interior of the materials.

  9. Mixed alkali effect in glasses containing MnO2

    International Nuclear Information System (INIS)

    Reddy, M. Sudhakara; Rajiv, Asha; Veeranna Gowda, V. C.; Chakradhar, R. P. S.; Reddy, C. Narayana

    2013-01-01

    Glass systems of the composition xLi 2 O−(25−x)K 2 O−70(0.4ZnO+0.6P 2 O 5 )+5MnO 2 (x = 4,8,12,16 and 20 mol %) have been prepared by melt quenching technique. The thermal and mechanical properties of the glasses have been evaluated as a function of mixed alkali content. Glass transition temperature and Vickers’s hardness of the glasses show a pronounced deviation from linearity at 12 mol%Li 2 O. Theoretically estimated elastic moduli of the glasses show small positive deviations from linearity. MAE in these properties has been attributed to the localized changes in the glass network. The absorption spectra of Mn 2+ ions in these glasses showed strong broad absorption band at 514 nm corresponding to the transition 6 A 1g (S)→ 4 T 1g (G), characteristic of manganese ions in octahedral symmetry. The fundamental absorption edge in UV region is used to study the optical transitions and electronic band structure. From UV absorption edge, optical band gap energies have been evaluated. Band gap energies of the glasses have exhibited MAE and shows minimum value for 12 mol%Li 2 O glass.

  10. Study of ZrO2-H2SO4-(NH4)2SO4(NH4Cl)-H2O systems

    International Nuclear Information System (INIS)

    Motov, D.L.; Sozinova, Yu.P.; Rys'kina, M.P.

    1988-01-01

    Regions of formation, composition and solubility of ammonium sulfatozirconates (ASZ) in ZrO 2 -H 2 SO 4 -(NH 4 ) 2 SO 4 (NH 4 Cl)-H 2 O systems at 25 and 75 deg C are studied by the isothermal method. Five ASZ: (NH 4 ) 2 Zr(OH) 2 (SO 4 ) 2 , NH 4 ZrOH(SO 4 ) 2 xH 2 O, NH 4 ZrO 0.5 (OH) 2 SO 4 x1.5H 2 O, (NH 4 ) 2 Zr(SO 4 ) 3 x2H 2 O, (NH 4 ) 4 Zr(SO 4 ) 4 x4H 2 O are detected, their properties are investigated. Main sulfates are new compounds never described ealier

  11. Effect of chitosan coating on the structural and magnetic properties of MnFe2O4 and Mn0.5Co0.5Fe2O4 nanoparticles

    Science.gov (United States)

    Mdlalose, W. B.; Mokhosi, S. R.; Dlamini, S.; Moyo, T.; Singh, M.

    2018-05-01

    We report the influence of polymer coatings on structural and magnetic properties of MnFe2O4 and Mn0.5Co0.5Fe2O4 nanoferrites synthesized by glycol thermal technique and then coated with chitosan viz. CHI-MnFe2O4 and CHI-Mn0.5Co0.5Fe2O4. The compounds were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), high-resolution scanning electron microscopy (HRSEM), Mössbauer spectroscopy and magnetization measurements. The powder XRD patterns of naked nanoferrites confirmed single-phase spinel cubic structure with an average crystallite size of 13 nm, while the coated samples exhibited an average particle size of 15 nm. We observed a reduction in lattice parameters with coating. HRTEM results correlated well with XRD results. 57Fe Mössbauer spectra showed ordered magnetic spin states in both nanoferrites. This study shows that coatings have significant effects on the structural and magnetic properties of Mn-nanoferrites. Magnetization studies performed at room temperature in fields up to 14 kOe revealed the superparamagnetic nature of both naked and coated nanoparticles with spontaneous magnetizations at room temperature of 49.2 emu/g for MnFe2O4, 23.6 emu/g for coated CHI-MnFe2O4 nanoparticles, 63.2 emu/g for Mn0.5Co0.5Fe2O4 and 33.2 emu/g for coated CHI-Mn0.5Co0.5Fe2O4 nanoparticles. We observed reduction in coercive fields due to coating. Overall, chitosan-coated manganese and manganese-cobalt nanoferrites present as suitable candidates for biomedical applications owing to physicochemical, and magnetic properties exhibited.

  12. The dimeric [V2O2F8]4− anion: Structural characterization of a magnetic basic-building-unit

    International Nuclear Information System (INIS)

    Lu, Hongcheng; Gautier, Romain; Li, Zuo-Xi; Jie, Wanqi; Liu, Zhengtang; Poeppelmeier, Kenneth R.

    2013-01-01

    New materials built from the [V 2 O 2 F 8 ] 4− anionic basic-building-unit (BBU) exhibit interesting magnetic properties owing to the proximity of the two d 1 V(IV) cations and the orbital interactions of fluoride and oxide ligands. In our search to target such materials, the vanadium oxide–fluoride compound [dpaH 2 ] 2 [V 2 O 2 F 8 ] in which a dimeric anion [V 2 O 2 F 8 ] 4− is isolated in a hydrogen bond network was hydrothermally synthesized (dpa=2,2′-dipyridylamine). This hydrogen bond network is able to stabilize the highly ionic species [V 2 O 2 F 8 ] 4− as demonstrated with bond valence calculations. The coordination of the O 2− /F − ordered ligands was investigated and antiferromagnetic coupling of the isolated BBU was measured. - The new hybrid compound [dpaH 2 ] 2 [V 2 O 2 F 8 ] built from the interesting [V 2 O 2 F 8 ] 4− magnetic basic-building-unit (BBU) was synthesized by the hydrothermal method. The coordination of the O 2− /F − ordered ligands was investigated by BVS calculations and antiferromagnetic coupling was measured. Highlights: ► A new vanadium oxyfluoride was synthesized by hydrothermal method. ► The Dimeric [V 2 O 2 F 8 ] 4− basic building unit is isolated in the hydrogen bond networks. ► The coordination of [V 2 O 2 F 8 ] 4− units to the extended structure is investigated. ► Isolated [V 2 O 2 F 8 ] 4− units exhibit antiferromagnetic coupling

  13. Different Dimensional and Structural Variations in Coordination Compounds of Cadmium, Manganese and Nickel Constructed from the Ligand 2,2'-Bipyidine-3,3',6,6'-tetracarboxylic Acid (H{sub 4}bptc)

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Jing; Yang, Tiantian; Fu, Lulu; Luo, Ya; Wu, Jiashou [Yangtze Univ., Jingzhou (China)

    2013-09-15

    The reactions of hydrated CdCl{sub 2}, MnCl{sub 2}, and NiCl{sub 2} with 2,2'-bipyidine-3,3',6,6'-tetracarboxylic acid (H{sub 4}bptc) afforded the mononuclear [Cd{sup II}(H{sub 2}bptc)(H{sub 2}O){sub 3}]·H{sub 2}O (1), linear [Cd(H{sub 2}bptc)(H{sub 2}O)]·3H{sub 2}O{sub n} (2), 3-D hetero-bimetallic [NaCd(Hbptc)(H{sub 2}O)] (3), layer [Mn(H{sub 2}bptc)(H{sub 2}O)]n (4) and a dinuclear compound [Ni{sub 2}(H{sub 2}bptc)-(H{sub 2}O){sub 2}]·6H{sub 2}O (5). These compounds have been characterized by elemental analysis, IR, and their structures have been determined by X-ray crystallography. The thermal stabilities of 1-3 were measured by thermogravimetric analysis (TGA) and their solid state luminescence properties together with the free ligand H{sub 4}bptc were investigated at room temperature.

  14. First-principle investigation on stability of Co-doped spinel λ-Mn4-xCoxO8

    Institute of Scientific and Technical Information of China (English)

    HUANG Ke-long; CHEN Chun-an; LIU Su-qin; LUO Qiong; LIU Zhi-guo

    2007-01-01

    The mechanism of stability of Co-doped spinel λ-MnO2 that is referred to as spinel LiχMn2O4 (χ=0) was studied by using the first-principle calculation method. The total energy and formation enthalpy can be decreased remarkably due to the Co substation,resulting in a more stable structure of λ-MnχCr2O4. The bond order and DOS analysis were given in detail to explain the nature of stability improvement. The calculated results show that as the content of Co dopant increases, the bond order of Mn-O becomes larger and the peak of density of states around Fermi level shifts toward lower energy. The charge density distribution illustrates that the Mn-O bonding is ionic and partially covalent, and the covalent Mn-O bonding becomes stronger with the increase of Co dopant content. The results confirm that the Co-doping will enhance the stability of λ-MnO2 and hence improve the electrochemistry performance of LiχMn2O4.

  15. Single Crystal Growth of Multiferroic Double Perovskites: Yb2CoMnO6 and Lu2CoMnO6

    Directory of Open Access Journals (Sweden)

    Hwan Young Choi

    2017-02-01

    Full Text Available We report on the growth of multiferroic Yb2CoMnO6 and Lu2CoMnO6 single crystals which were synthesized by the flux method with Bi2O3. Yb2CoMnO6 and Lu2CoMnO6 crystallize in a double-perovskite structure with a monoclinic P21/n space group. Bulk magnetization measurements of both specimens revealed strong magnetic anisotropy and metamagnetic transitions. We observed a dielectric anomaly perpendicular to the c axis. The strongly coupled magnetic and dielectric states resulted in the variation of both the dielectric constant and the magnetization by applying magnetic fields, offering an efficient approach to accomplish intrinsically coupled functionality in multiferroics.

  16. Bis(2,2′-bipyridyl-κ2N,N′(sulfato-κ2O,O′cobalt(II ethane-1,2-diol monosolvate

    Directory of Open Access Journals (Sweden)

    Lin Chen

    2011-01-01

    Full Text Available The title compound, [Co(SO4(C10H8N22]·C2H6O2, has the Co2+ ion in a distorted octahedral CoN4O2 coordination geometry. A twofold rotation axis passes through the Co and S atoms, and through the mid-point of the C—C bond of the ethanediol molecule. In the crystal, the [CoSO4(C10H8N22] and C2H6O2 units are held together by a pair of O—H...O hydrogen bonds.

  17. Poly[tetraaqua(μ6-9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylatodimanganese(II

    Directory of Open Access Journals (Sweden)

    Rui Xu

    2012-07-01

    Full Text Available The title complex, [Mn2(C18H4O10(H2O4]n, was synthesized from manganese(II chloride tetrahydrate and 9,10-dioxo-9,10-dihydroanthracene-1,4,5,8-tetracarboxylic acid (H4AQTC in water. The anthraquinone unit is located about a crystallographic center of inversion. Each asymmetric unit therefore contains one MnII atom, two water ligands and one half AQTC4− anion. The MnII atom is coordinated in a distorted octahedral geometry by four O atoms from three AQTC4− ligands and two water O atoms. Two of the carboxylate groups coordinate one MnII atom in a chelating mode, whereas the others each coordinate two MnII atoms. Each AQTC4− tetra-anion therefore coordinates six different MnII ions and, as a result, a three-dimensional coordination polymer is formed. O—H...O hydrogen bonds, some of them bifurcated, between water ligands and neighboring water or anthraquinone ligands are observed in the crystal structure.

  18. Semiconducting perovskites (2-XC6H4C2H4NH3)2SnI4 (X = F, Cl, Br): steric interaction between the organic and inorganic layers.

    Science.gov (United States)

    Xu, Zhengtao; Mitzi, David B; Dimitrakopoulos, Christos D; Maxcy, Karen R

    2003-03-24

    Two new semiconducting hybrid perovskites based on 2-substituted phenethylammonium cations, (2-XC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) (X = Br, Cl), are characterized and compared with the previously reported X = F compound, with a focus on the steric interaction between the organic and inorganic components. The crystal structure of (2-ClC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) is solved in a disordered subcell [C2/m, a = 33.781(7) A, b = 6.178(1) A, c = 6.190(1) A, beta = 90.42(3)(o), and Z = 2]. The structure is similar to the known (2-FC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) structure with regard to both the conformation of the organic cations and the bonding features of the inorganic sheet. The (2-BrC(6)H(4)C(2)H(4)NH(3))(2)SnI(4) system adopts a fully ordered monoclinic cell [P2(1)/c, a = 18.540(2) A, b = 8.3443(7) A, c = 8.7795(7) A, beta = 93.039(1)(o), and Z = 2]. The organic cation adopts the anti conformation, instead of the gauche conformation observed in the X = F and Cl compounds, apparently because of the need to accommodate the additional volume of the bromo group. The steric effect of the bromo group also impacts the perovskite sheet, causing notable distortions, such as a compressed Sn-I-Sn bond angle (148.7(o), as compared with the average values of 153.3 and 154.8(o) for the fluoro and chloro compounds, respectively). The optical absorption features a substantial blue shift (lowest exciton peak: 557 nm, 2.23 eV) relative to the spectra of the fluoro and chloro compounds (588 and 586 nm, respectively). Also presented are transport properties for thin-film field-effect transistors (TFTs) based on spin-coated films of the two hybrid semiconductors.

  19. Synthesis of Li-Mn-O mesocrystals with controlled crystal phases through topotactic transformation of MnCO₃.

    Science.gov (United States)

    Dang, Feng; Hoshino, Tatsuhiko; Oaki, Yuya; Hosono, Eiji; Zhou, Haoshen; Imai, Hiroaki

    2013-03-21

    Mesocrystals of Li-Mn-O compounds, such as LiMn2O4, Li2MnO3, and LiMnO2-Li2MnO3, consisting of oriented nanoscale units were selectively produced under hydrothermal conditions from biomimetically prepared MnCO3 mesocrystals. Topotactic transformation through the intermediate phase of Mn5O8 inheriting a hierarchical structure of the MnCO3 precursor was essential for the formation of the mesocrystal compounds. The crystal phases were successfully controlled by varying the conditions for the hydrothermal reactions. The Li-Mn-O mesocrystals have considerable potential as cathodes of Li-ion batteries.

  20. Synthesis and characteristics of a novel 3-D organic amine oxalate: (enH2)1.5[Bi3(C2O4)6(CO2CONHCH2CH2NH3)].6.5H2O

    International Nuclear Information System (INIS)

    Yu Xiaohong; Zhang Hanhui; Cao Yanning; Chen Yiping; Wang Zhen

    2006-01-01

    A novel 3-D compound of (enH 2 ) 1.5 [Bi 3 (C 2 O 4 ) 6 (CO 2 CONHCH 2 CH 2 NH 3 )].6.5H 2 O has been hydrothermally synthesized and characterized by IR, ultraviolet-visible diffuse reflection integral spectrum (UV-Vis DRIS), fluorescence spectra, TGA and single crystal X-ray diffraction. It crystallizes in the monoclinic system, space group C2/c with a=31.110(8)A, b=11.544(3)A, c=22.583(6)A, β=112.419(3) o , V=7497(3)A 3 , Z=8, R 1 =0.0463 and wR 2 =0.1393 for unique 7686 reflections I>2σ(I). In the title compound, the Bi atoms have eight-fold and nine-fold coordination with respect to the oxygen atoms, with the Bi atoms in distorted dodecahedron and monocapped square antiprism, respectively. The 3-D framework of the title compound contains channels and is composed of linkages between Bi atoms and oxalate units, forming honeycomb-like layers with two kinds of 6+6 membered aperture, and pillared by oxalate ligands and monamide groups. The channels have N-ethylamine oxalate monamide group - CO 2 CONHCH 2 CH 2 NH 3 + , which is formed by the in situ reaction of en and oxalate acid. At room temperature, the complex exhibits intense blue luminescence with an emission peak at 445nm

  1. Structural phase transitions in the ordered double perovskite Sr2MnTeO6

    International Nuclear Information System (INIS)

    Ortega-San Martin, L; Chapman, J P; Hernandez-Bocanegra, E; Insausti, M; Arriortua, M I; Rojo, T

    2004-01-01

    The crystal structure of the ordered double perovskite Sr 2 MnTeO 6 has been refined at ambient temperature from high resolution neutron and x-ray powder diffraction data in the monoclinic space group P 12 1 /n 1 with a 5.7009(1) A, b = 5.6770(1) A, c = 8.0334(1) A and β = 90.085(1) deg. This represents a combination of in-phase (+) and out-of-phase (-) rotations of virtually undistorted MnO 6 and TeO 6 octahedra in the (-+) sense about the axes of the ideal cubic perovskite. High temperature x-ray powder diffraction shows three structural phase transitions at approximately 250, 550 and 675 deg. C, each corresponding to the disappearance of rotations about one of these axes. The first transition was analysed by differential scanning calorimetry and showed a thermal hysteresis with an enthalpy of 0.55 J g -1 . We propose the (P12 1 /n1 → I12/m1 → I4/m → Fm3barm) sequence of structural transitions which has not been previously reported for a double perovskite oxide

  2. Coating effect of LiFePO4 and Al2O3 on Li1.2Mn0.54Ni0.13Co0.13O2 cathode surface for lithium ion batteries

    Science.gov (United States)

    Seteni, Bonani; Rapulenyane, Nomasonto; Ngila, Jane Catherine; Mpelane, Siyasanga; Luo, Hongze

    2017-06-01

    Lithium-manganese-rich cathode material Li1.2Mn0.54Ni0.13Co0.13O2 is prepared by combustion method, and then coated with nano-sized LiFePO4 and nano-sized Al2O3 particles via a wet chemical process. The as-prepared Li1.2Mn0.54Ni0.13Co0.13O2, LiFePO4-coated Li1.2Mn0.54Ni0.13Co0.13O2 and Al2O3-coated Li1.2Mn0.54Ni0.13Co0.13O2 are characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The scanning electron microscopy shows the agglomeration of the materials and their nanoparticle size ∼100 nm. The transmission electron microscopy confirms that LiFePO4 forms a rough mat-like surface and Al2O3 remain as islandic particles on the surface of the Li1.2Mn0.54Ni0.13Co0.13O2 material. The Li1.2Mn0.54Ni0.13Co0.13O2 coated with LiFePO4 and Li1.2Mn0.54Ni0.13Co0.13O2 coated with Al2O3 exhibits improved electrochemical performance. The initial discharge capacity is enhanced to 267 mAhg-1 after the LiFePO4 coating and 285 mAhg-1 after the Al2O3 coating compared to the as-prepared Li1.2Mn0.54Ni0.13Co0.13O2 material that has an initial discharge capacity of 243 mAhg-1. Galvanostatic charge-discharge tests at C/10 display longer activation of Li2MnO3 phase and higher capacity retention of 88% after 20 cycles for Li1.2Mn0.54Ni0.13Co0.13O2-LiFePO4 compared to Li1.2Mn0.54Ni0.13Co0.13O2-Al2O3 of 80% after 20 cycles and LMNC of 80% after 20 cycles. Meanwhile Li1.2Mn0.54Ni0.13Co0.13O2-LiFePO4 also shows higher rate capability compared to Li1.2Mn0.54Ni0.13Co0.13O2-Al2O3.

  3. Positron annihilation characterization of free volume in micro- and macro-modified Cu0.4Co0.4Ni0.4Mn1.8O4 ceramics

    International Nuclear Information System (INIS)

    Klym, H.; Ingram, A.; Shpotyuk, O.; Hadzaman, I.; Solntsev, V.; Hotra, O.; Popov, A.

    2016-01-01

    Free volume and pore size distribution size in functional micro and macro-micro-modified Cu 0.4 Co 0.4 Ni 0.4 Mn 1.8 O 4 ceramics are characterized by positron annihilation lifetime spectroscopy in comparison with Hg-porosimetry and scanning electron microscopy technique. Positron annihilation results are interpreted in terms of model implication positron trapping and ortho-positronium decaying. It is shown that free volume of positron traps are the same type for macro and micro modified Cu 0.4 Co 0.4 Ni 0.4 Mn 1.8 O 4 ceramics. Classic Tao-Eldrup model in spherical approximation is used to calculation of the size of nanopores smaller than 2 nm using the ortho-positronium lifetime.

  4. The assessment of the energetic compound 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-Hexaazaisowurtzitane (CL-20) degradability in soil

    International Nuclear Information System (INIS)

    Strigul, Nikolay; Braida, Washington; Christodoulatos, Christos; Balas, Wendy; Nicolich, Steven

    2006-01-01

    CL-20 is a relatively new energetic compound with applications in explosive and propellant formulations. Currently, information about the fate of CL-20 in ecological systems is scarce. The aim of this study is to evaluate the biodegradability of CL-20 in soil environments. Four soils were used where initial CL-20 concentrations (above water solubility) ranged from 125 to 1500 mg of CL-20 per kg dry soil (corresponding to the concentrations derived from unexploded ordnance, low order detonation, or manufacturing spills). CL-20 appears to be biodegradable in soil under anaerobic conditions, and additions of organic substrates can substantially accelerate this process. However, CL-20 is not degraded in soil under aerobic conditions kept in the dark at temperatures up to 30 deg. C without organic amendments. Additions of starch or cellulose promote the biodegradation of CL-20 under aerobic conditions. Soil microbial community mediated biodegradation and plant uptake appears to enhance CL-20 biodegradation, the latter suggesting a possible route for CL-20 to entry in the food chain. - Biodegradation and plant uptake suggest possible entry of CL-20 into food chain

  5. K{sub 1.33}Mn{sub 8}O{sub 16} as an electrocatalyst and a cathode

    Energy Technology Data Exchange (ETDEWEB)

    Jalili, Seifollah, E-mail: sjalili@kntu.ac.ir [Department of Chemistry, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Computational Physical Sciences Research Laboratory, School of Nano-Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Moharramzadeh Goliaei, Elham [Department of Chemistry, K. N. Toosi University of Technology, P.O. Box 15875-4416, Tehran (Iran, Islamic Republic of); Schofield, Jeremy [Chemical Physics Theory Group, Department of Chemistry, University of Toronto, 80 Saint George Street, Toronto, Ontario, Canada M5S 3H6 (Canada)

    2017-02-15

    Density functional theory (DFT) calculations are carried out to investigate the electronic, magnetic and thermoelectric properties of bulk and nanosheet K{sub 1.33}Mn{sub 8}O{sub 16} materials. The catalytic activity and cathodic performance of bulk and nanosheet structures are examined using the Tran-Blaha modified Becke-Johnson (TB-mBJ) exchange potential. Electronic structure calculations reveal an anti-ferromagnetic ground state, with a TB-mMBJ band gap in bulk K{sub 1.33}Mn{sub 8}O{sub 16} that is in agreement with experimental results. Density of state plots indicate a partial reduction of Mn{sup 4+} ions to Mn{sup 3+}, without any obvious sign of Jahn-Teller distortion. Moreover, use of the O p-band center as a descriptor of catalytic activity suggests that the nanosheet has enhanced catalytic activity compared to the bulk structure. Thermoelectric parameters such as the Seebeck coefficient, electrical conductivity, and thermal conductivity are also calculated, and it is found that the Seebeck coefficients decrease with increasing temperature. High Seebeck coefficients for both spin-up and spin-down states are found in the nanosheet relative to their value in the bulk K{sub 1.33}Mn{sub 8}O{sub 16} structure, whereas the electrical and thermal conductivity are reduced relative to the bulk. In addition, figures of merit values are calculated as a function of the chemical potential and it is found that the nanosheet has a figure of merit of ~1 at room temperature, compared to 0.5 for the bulk material. All results suggest that K{sub 1.33}Mn{sub 8}O{sub 16} nanosheets can be used both as a material in waste heat recovery and as an electrocatalyst in fuel cells and batteries. - Graphical abstract: K{sub 1.33}Mn{sub 8}O{sub 16}: bulk and nanosheet. - Highlights: • Electronic properties of bulk and nanosheet forms of K{sub 1.33}Mn{sub 8}O{sub 16} have been studied. • The K{sub 1.33}Mn{sub 8}O{sub 16} nanosheet is a semiconductor while the bulk is a metal. • K

  6. Tris(2,2′-bipyridine-κ2N,N′cobalt(III bis[bis(pyridine-2,6-dicarboxylato-κ3O2,N,O6cobaltate(III] perchlorate dimethylformamide hemisolvate 1.3-hydrate

    Directory of Open Access Journals (Sweden)

    Irina A. Golenya

    2012-10-01

    Full Text Available In the title compound, [Co(C10H8N23][Co(C7H3NO42]2(ClO4·0.5C3H7NO·1.3H2O, the CoIII atom in the complex cation is pseudooctahedrally coordinated by six N atoms of three chelating bipyridine ligands. The CoIII atom in the complex anion is coordinated by two pyridine N atoms and four carboxylate O atoms of two doubly deprotonated pyridine-2,6-dicarboxylate ligands in a distorted octahedral geometry. One dimethylformamide solvent molecule and two water molecules are half-occupied and one water molecule is 0.3-occupied. O—H...O hydrogen bonds link the water molecules, the perchlorate anions and the complex anions. π–π interactions between the pyridine rings of the complex anions are also observed [centroid–centroid distance = 3.804 (3 Å].

  7. High-pressure phase of the cubic spinel NiMn2O4

    DEFF Research Database (Denmark)

    Åsbrink, S.; Waskowska, A.; Olsen, J. Staun

    1998-01-01

    experimental uncertainty, there is no volume change at the transition. The cia ratio of the tetragonal spinel is almost independent of pressure and equal to 0.91. The phase transition is attributed to the Jahn-Teller-type distortion and the ionic configurationcan be assumed as (Mn3+)(tetr)[Ni2+Mn3+](oct......It has been observed that the fee spinel NiMn2O4 transforms to a tetragonal structure at about 12 GPa. The tetragonal phase does not revert to the cubic phase upon decompression and its unit-cell constants at ambient pressure are a(0)=8.65(8) and c(0)=7.88(15) Angstrom (distorted fee). Within thr......). The bulk modulus of the cubic phase is 206(4) GPa....

  8. 8-Hydroxy-2-methylquinolinium tetrachlorido(pyridine-2-carboxylato-κ2N,Ostannate(IV

    Directory of Open Access Journals (Sweden)

    Ezzatollah Najafi

    2011-02-01

    Full Text Available In the reaction of pyridine-2-carboxylic acid and stannic chloride in the presence of 2-methyl-8-hydroxyquinoline, the 2-methyl-8-hydroxyquinoline is protonated, yielding the title salt, (C10H10NO[SnCl4(C6H4NO2]. The SnIV atom in the anion is N,O-chelated by a pyridine-2-carboxylate in a cis-SnNOCl4 octahedral geometry. The cation is linked to the anion by an O—H...O hydrogen bond.

  9. New metal-organic frameworks of [M(C6H5O7)(C6H6O7)(C6H7O7)(H2O)] . H2O (M=La, Ce) and [Ce2(C2O4)(C6H6O7)2] . 4H2O

    International Nuclear Information System (INIS)

    Weng Shengfeng; Wang, Yun-Hsin; Lee, Chi-Shen

    2012-01-01

    Two novel materials, [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2), with a metal-organic framework (MOF) were prepared with hydrothermal reactions and characterized with photoluminescence, magnetic susceptibility, thermogravimetric analysis and X-ray powder diffraction in situ. The crystal structures were determined by single-crystal X-ray diffraction. Compound 1 crystallized in triclinic space group P1-bar (No. 2); compound 2 crystallized in monoclinic space group P2 1 /c (No. 14). The structure of 1 is built from a 1D MOF, composed of deprotonated citric ligands of three kinds. Compound 2 contains a 2D MOF structure consisting of citrate and oxalate ligands; the oxalate ligand arose from the decomposition in situ of citric acid in the presence of Cu II ions. Photoluminescence spectra of compounds 1b and 2 revealed transitions between the 5d 1 excited state and two levels of the 4f 1 ground state ( 2 F 5/2 and 2 F 7/2 ). Compounds 1b and 2 containing Ce III ion exhibit a paramagnetic property with weak antiferromagnetic interactions between the two adjacent magnetic centers. - Graphical Abstract: [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2)—with 1D and 2D structures were synthesized and characterized. Highlights: ► Two MOF – [M(C 6 H 5 O 7 )(C 6 H 6 O 7 )(C 6 H 7 O 7 )(H 2 O)] . H 2 O (M=La(1a), Ce(1b)) and [Ce 2 (C 2 O 4 )(C 6 H 6 O 7 ) 2 ] . 4H 2 O (2) – with 1D and 2D structures. ► The adjacent chains of the 1D framework were correlated with each other through an oxalate ligand to form a 2D layer structure. ► The source of the oxalate ligand was the decomposition in situ of citric acid oxidized in the presence of Cu II ions.

  10. Study of the efficiency of AgCl, In2O3, Ga2O3, NaF, LiF and SrF2 as spectrographic carriers in the quantitative analysis of eighteen microcompound elements in uranium

    International Nuclear Information System (INIS)

    Gomes, R.P.; Lordello, A.R.; Abrao, A.

    1977-01-01

    A comparative study of the efficiency of some spectrochemical carriers (AgCl, In 2 O 3 , Ga 2 O 3 , NaF, LiF and SrF 2 ) is presented for the quantitative spectrographic analysis of Ag, Al, B, Bi, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Ni, P, Pb, Si, Sn, V and Zn in uranium and its compounds. The volatility behaviour of the eighteen elements was verified by means of the moving plate technique for each of the mentioned carriers. The final aim was the selection of the carriers for the determination of trace amounts of the impurities. The best results were obtained with 4% In 2 O 3 , 6% AgCl and 6% NaF in a U 3 O 8 matrix. The sensitivities for some elements were extended to fractions of p.p.m. The precision, accuracy and acceptability of the method were calculated for all elements. The total error values are approximately in the range of 16-45% [pt

  11. Li2Sr4B12O23: A new alkali and alkaline-earth metal mixed borate with [B10O18]6− network and isolated [B2O5]4− unit

    International Nuclear Information System (INIS)

    Zhang Min; Pan Shilie; Han Jian; Yang Zhihua; Su Xin; Zhao Wenwu

    2012-01-01

    A novel ternary lithium strontium borate Li 2 Sr 4 B 12 O 23 crystal with size up to 20 mm×10 mm×4 mm has been grown via the top-seeded solution growth method below 730 °C. Single-crystal XRD analyses showed that Li 2 Sr 4 B 12 O 23 crystallizes in the monoclinic space group P2 1 /c with a=6.4664(4) Å, b=8.4878(4) Å, c=15.3337(8) Å, β=102.02(3)°, Z=2. The crystal structure is composed of [B 10 O 18 ] 6− network and isolated [B 2 O 5 ] 4− unit. The IR spectrum further confirmed the presence of both BO 3 and BO 4 groups. TG-DSC and Transmission spectrum were reported. Band structures and density of states were calculated. - Graphical abstract: A new phase, Li 2 Sr 4 B 12 O 23 , has been discovered in the ternary M 2 O–M′O–B 2 O 3 (M=alkali-metal, M′=alkalineearth metal) system. The crystal structure consists of [B 10 O 18 ] 6− network and isolated [B 2 O 5 ] 4− unit. Highlights: ► Li 2 Sr 4 B 12 O 23 is a a novel borate discovered in the M 2 O–M′O–B 2 O 3 (M=alkali-metal, M′=alkaline-earth metal) system. ► Li 2 Sr 4 B 12 O 23 crystal structure has a three-dimensional crystal structure with [B 10 O 18 ] 6− network and isolated [B 2 O 5 ] 4− unit. ► Sr 1 and Sr 2 are located in two different channels constructed by 3 ∞ [B 10 O 18 ] network.

  12. Magnetic signature of charge ordering in Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 and Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4

    CERN Document Server

    Verhoeven, V W J; Mulder, F M

    2002-01-01

    The stoichiometric compound LiMn sub 2 O sub 4 is known to show charge ordering with well-defined Mn sup 3 sup + and Mn sup 4 sup + sites just below room temperature (RT). Above RT the electrons are hopping rapidly between sites. For lithium-ion batteries the material Li[Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 is technologically relevant. Due to the small amount of Li on the Mn site, the low-T regular ordering of the Mn charge appears to be destroyed completely, as is evidenced by neutron diffraction in the magnetically ordered state. However, the charges are still fixed in an irregular fashion, as can also be deduced from sup 7 Li nuclear magnetic resonance measurements. In the lithium-extracted compound Li sub 0 sub . sub 2 [Mn sub 1 sub . sub 9 sub 6 Li sub 0 sub . sub 0 sub 4]O sub 4 , predominantly Mn sup 4 sup + is present. Neutron diffraction in the magnetically ordered state shows a well-defined antiferromagnetic ordering, with doubling of the unit cell in three directions. Clear...

  13. Solid-liquid stable phase equilibria of the ternary systems MgCl2 + MgB6O10+ H2O AND MgSO4 + MgB6O10 + H2O at 308.15 K

    Directory of Open Access Journals (Sweden)

    Lingzong Meng

    2014-03-01

    Full Text Available The solubilities and the relevant physicochemical properties of the ternary systems MgCl2 + MgB6O10 + H2O and MgSO4 + MgB6O10 + H2O at 308.15 K were investigated using an isothermal dissolution method. It was found that there is one invariant point, two univariant curves, and two crystallization regions of the systems. The systems belong to a simple co-saturated type, and neither double salts nor solid solutions were found. Based on the extended HW model and its temperature-dependent equations, the single-salt Pitzer parameters β(0, β(1, β(2 and CØ for MgCl2, MgSO4, and Mg(B6O7(OH6, the mixed ion-interaction parameters θCl,B6O10, θSO4,B6O10, ΨMg,Cl,B6O10, ΨMg,SO4,B6O10 of the systems at 308.15 K were fitted, In addition, the average equilibrium constants of the stable equilibrium solids at 308.15 K were obtained by a method using the activity product constant. Then the solubilities of the ternary systems are calculated. The calculated solubilities agree well with the experimental values.

  14. Luminescence Characteristics of ZnGa2O4 Thick Film Doped with Mn2+ and Cr3+ at Various Sintering Temperatures

    Science.gov (United States)

    Cha, Jae Hyeok; Kim, Kyung Hwan; Park, Yong Seo; Kwon, Sang Jik; Choi, Hyung Wook

    2007-10-01

    ZnGa2O4 phosphor separately doped with Mn2+ and Cr3+ was synthesized by solid-state reaction, and thick films were deposited by screen printing. The X-ray diffraction (XRD) patterns of ZnGa2O4 phosphor thick films show a (311) main peak and a spinal phase. Uniform distribution and filled morphology of the doped ZnGa2O4 phosphor thick films were formed at the sintering temperature of 1100 °C. The CL spectrum of Mn2+-doped ZnGa2O4 shows the main peak of 512 nm green emission with the 4T1→6A1 transition of Mn2+ ions and the CL spectrum of Cr3+-doped ZnGa2O4 shows the main peak of 716 nm red emission with the 2E→4A2 transition of Cr3+ ions.

  15. Lithiotantite, ideally LiTa3O8

    Directory of Open Access Journals (Sweden)

    Aba C. Persiano

    2012-05-01

    Full Text Available Lithiotantite (lithium tritantalum octaoxide and lithiowodginite are natural dimorphs of LiTa3O8, corresponding to the laboratory-synthesized L-LiTa3O8 (low-temperature form and M-LiTa3O8 (intermediate-temperature form phases, respectively. Based on single-crystal X-ray diffraction data, this study presents the first structure determination of lithiotantite from a new locality, the Murundu mine, Jenipapo District, Itinga, Minas Gerais, Brazil. Lithiotantite is isotypic with LiNb3O8 and its structure is composed of a slightly distorted hexagonal close-packed array of O atoms stacked in the [-101] direction, with the metal atoms occupying half of the octahedral sites. There are four symmetrically non-equivalent cation sites, with three of them occupied mainly by (Ta5+ + Nb5+ and one by Li+. The four distinct octahedra share edges, forming two types of zigzag chains (A and B extending along the b axis. The A chains are built exclusively of (Ta,NbO6 octahedra (M1 and M2, whereas the B chains consist of alternating (Ta,NbO6 and LiO6 octahedra (M3 and M4, respectively. The average M1—O, M2O, M3—O and M4O bond lengths are 2.011, 2.004, 1.984, and 2.188 Å, respectively. Among the four octahedra, M3 is the least distorted and M4 the most. The refined Ta contents at the M1, M2 and M3 sites are 0.641 (2, 0.665 (2, and 0.874 (2, respectively, indicating a strong preference of Ta5+ for M3 in the B chain. The refined composition of the crystal investigated is Li0.96Mn0.03Na0.01Nb0.82Ta2.18O8.

  16. Crystal structures of N-(4-chlorophenyl-2-[(4,6-diaminopyrimidin-2-ylsulfanyl]acetamide and N-(3-chlorophenyl-2-[(4,6-diaminopyrimidin-2-ylsulfanyl]acetamide

    Directory of Open Access Journals (Sweden)

    S. Subasri

    2017-04-01

    Full Text Available The title compounds, C12H12ClN5OS, (I, and C12H12ClN5OS, (II, are 2-[(diaminopyrimidin-2-ylsulfanyl]acetamides. Compound (II, crystallizes with two independent molecules (A and B in the asymmetric unit. In each of the molecules, in both (I and (II, an intramolecular N—H...N hydrogen bond forms an S(7 ring motif. The pyrimidine ring is inclined to the benzene ring by 42.25 (14° in (I, and by 59.70 (16 and 62.18 (15° in molecules A and B, respectively, of compound (II. In the crystal of (I, molecules are linked by pairs of N—H...N hydrogen bonds, forming inversion dimers with an R22(8 ring motif. The dimers are linked via bifurcated N—H...O and C—H...O hydrogen bonds, forming corrugated layers parallel to the ac plane. In the crystal of (II, the A molecules are linked through N—H...O and N—H...Cl hydrogen bonds, forming layers parallel to (100. The B molecules are also linked by N—H...O and N—H...Cl hydrogen bonds, also forming layers parallel to (100. The parallel layers of A and B molecules are linked via N—H...N hydrogen bonds, forming a three-dimensional structure.

  17. Modelling of phase equilibria in CH4–C2H6–C3H8–nC4H10–NaCl–H2O systems

    International Nuclear Information System (INIS)

    Li, Jun; Zhang, Zhigang; Luo, Xiaorong; Li, Xiaochun

    2015-01-01

    Highlights: • A new model was established for the phase equilibria of C1–C2–C3–nC4–brine systems. • The model can reproduce of hydrocarbon–brine equilibria to high T&P and salinity. • The model can well predict H 2 O solubility in light hydrocarbon rich phases. - Abstract: A thermodynamic model is presented for the mutual solubility of CH 4 –C 2 H 6 –C 3 H 8 –nC 4 H 10 –brine systems up to high temperature, pressure and salinity. The Peng–Robinson model is used for non-aqueous phase fugacity calculations, and the Pitzer model is used for aqueous phase activity calculations. The model can accurately reproduce the experimental solubilities of CH 4 , C 2 H 6 , C 3 H 8 and nC 4 H 10 in water or NaCl solutions and H 2 O solubility in the non-aqueous phase. The experimental data of mutual solubility for the CH 4 –brine subsystem are sufficient for temperatures exceeding 250 °C, pressures exceeding 1000 bar and NaCl molalities greater than 6 molal. Compared to the CH 4 –brine system, the mutual solubility data of C 2 H 6 –brine, C 3 H 8 –brine and nC 4 H 10 –brine are not sufficient. Based on the comparison with the experimental data of H 2 O solubility in C 2 H 6 -, C 3 H 8 - or nC 4 H 10 -rich phases, the model has an excellent capability for the prediction of H 2 O solubility in hydrocarbon-rich phases, as these experimental data were not used in the modelling. Predictions of hydrocarbon solubility (at temperatures up to 200 °C, pressures up to 1000 bar and NaCl molalities greater than 6 molal) were made for the C 2 H 6 –brine, C 3 H 8 –brine and nC 4 H 10 –brine systems. The predictions suggest that increasing pressure generally increases the hydrocarbon solubility in water or brine, especially in the lower-pressure region. Increasing temperature usually decreases the hydrocarbon solubility at lower temperatures but increases the hydrocarbon solubility at higher temperatures. Increasing water salinity dramatically decreases

  18. Lithium Insertion in LiCr3O8, NaCr3O8, and KCr3O8 at Room Temperature and at 125°C

    DEFF Research Database (Denmark)

    Koksbang, R.; Fauteux, D.; Norby, P.

    1989-01-01

    Lithium insertion and deinsertion reactions have been carried out with LiCr3O8, NaCr3O8, and KCr3O8 chemically andelectrochemically at room temperature and at 125°C. The electrochemical experiments were performed with a nonaqueousliquid electrolyte at room temperature and with a polymer electroly...... is close to 4Li/NaCr3O8 and 1.3Li/KCr3O8.Lithium ion diffusion coefficients are similar for the two compounds in the comparable composition range.Thermally, the fully lithiated compounds appear to be as stable as the pristine materials.......Lithium insertion and deinsertion reactions have been carried out with LiCr3O8, NaCr3O8, and KCr3O8 chemically andelectrochemically at room temperature and at 125°C. The electrochemical experiments were performed with a nonaqueousliquid electrolyte at room temperature and with a polymer electrolyte....... At elevated temperatures, the isostructural compounds NaCr3O8 and KCr3O8 are able to accommodate morethan 4Li/MCr3O8. During this process, minor structural changes are observed. At room temperature, NaCr3O8 and KCr3O8also accommodate Li topotactically, but the maximum number of Li inserted per formula...

  19. Effects of cationic substitution on the electronic and magnetic properties of manganocuprate with a layered Eu3Ba2Mn2Cu2O12 structure

    International Nuclear Information System (INIS)

    Matsubara, Ichiro; Funahashi, Ryoji; Ueno, Kazuo; Ishikawa, Hiroshi; Kida, Noriaki; Ohno, Nobuhito

    1998-01-01

    Systematic studies on the effect of substitutions on the layered manganocuprate Eu 3 Ba 2 Mn 2 Cu 2 O 12 have been conducted. To introduce holes, the authors have made substitutions of Ca for Eu and/or Sc for Mn, (Eu 3-x Ca x )Ba 2 (Mn 2-y Sc y )Cu 2 O 12 . Single-phase compounds are obtained over a fairly wide range of x and y values for x ≤ 0.7 (y = 0), x ≤ 0.5 (y = 0.5), and x ≤ 0.1 (y = 1.0). The doped holes are received predominantly at the Mn-O site and change the charge of Mn from 3+ to 4+, and no superconductivity has been obtained for any sample. The electronic ground state of (Eu 3-x Ca x )Ba 2 (Mn 2-y Sc y )Cu 2 O 12 is discussed by comparing with that of the three-dimensional perovskite La 1-x Ca x MnO 3 and K 2 NiF 4 -type La 1-x Sr 1+x MnO 4 compounds. The substitution of Sr for Ba gives rise to a different crystal structure, the Sr 3 Ti 2 O 7 structure

  20. Analysis of (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8}:Eu{sup 2+}, Mn{sup 2+} phosphors for application in solid state lighting

    Energy Technology Data Exchange (ETDEWEB)

    Han, J.K. [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); Piqutte, A.; Hannah, M.E. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Drive Beverly, MA 01915 (United States); Hirata, G.A. [Centro de Nanociencias y Nanotecnolgía, Universidad Nacional Autónoma de México, Km. 107 Carretera Tijuana-Ensenada Apdo, Ensenada MX CP 22860 (Mexico); Talbot, J.B. [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); University of California, San Diego, Department of Nanoengineering, La Jolla, CA 92093 (United States); Mishra, K.C. [OSRAM SYLVANIA Central Research, 71 Cherry Hill Drive Beverly, MA 01915 (United States); McKittrick, J., E-mail: jmckittrick@ucsd.edu [University of California, San Diego, Materials Science and Engineering Program, La Jolla, CA 92093 (United States); University of California, San Diego, Department of Mechanical and Aerospace Engineering, La Jolla, CA 92093 (United States)

    2014-04-15

    The luminescence properties of Eu{sup 2+} and Mn{sup 2+} co-activated (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8} phosphors prepared by combustion synthesis were studied. Eu{sup 2+}-activated (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8} has a broad blue emission band centered at 450–485 nm and Eu{sup 2+}–Mn{sup 2+}-activated (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8} exhibits a red emission around 620–703 nm, depending on the relative concentrations of Ba, Ca and Sr. The particle size of Eu{sup 2+} and Mn{sup 2+} co-activated (Ba,Ca){sub 3}MgSi{sub 2}O{sub 8} ranges from 300 nm to 1 μm depending on the metal ion and are agglomerated due to post-synthesis, high temperature annealing. The green emission of Ba{sub 3}MgSi{sub 2}O{sub 8} originates from secondary phases (Ba{sub 2}SiO{sub 4} and BaMgSiO{sub 4}) confirmed by emission spectra and X-ray diffraction patterns. The secondary phases of Ba{sub 3}MgSi{sub 2}O{sub 8} are removed by the addition of Sr. The quantum efficiencies range from 45% to 70% under 400 nm excitation and the lifetime of red emission of Ba{sub 3}MgSi{sub 2}O{sub 8} decreases significantly with increasing temperature, which is 54% at 400 K of that at 80 K compared to that of blue emission (90% at 400 K of that at 80 K). -- highlights: • (Ba,Ca,Sr){sub 3}MgSi{sub 2}O{sub 8}:Eu{sup 2+}, Mn{sup 2+} phosphors were prepared by a combustion synthesis method. • The emission spectra consist of broad blue-emission band and red-emission band. • The quantum efficiencies range between 45% and 70%, depending on the relative concentrations of Ba, Ca and Sr. • The secondary phases were eliminated by additions of Sr. • Lifetime of the red-emission decreases with increasing temperature, suggesting that these phosphors are not useful for solid state lighting applications.

  1. (Dimethylformamide-κO(2-hydroxybenzoato-κ2O1,O1′[tris(1-methyl-1H-benzimidazol-2-ylmethyl-κN3amine-κN]manganese(II perchlorate dimethylformamide monosolvate

    Directory of Open Access Journals (Sweden)

    Baoliang Qi

    2010-10-01

    Full Text Available In the title complex, [Mn(C7H5O3(C27H27N7(C3H7NO]ClO4·C3H7NO, the MnII ion is coordinated in a slightly distorted monocapped trigonal-prismatic geometry. The tris(1-methyl-1H-benzimidazol-2-ylmethylamine (Mentb ligand coordinates in a tetradentate mode and the coordination is completed by a bis-chelating salicylate ligand and a dimethylformamide ligand. The hydroxy group and the ortho H atoms of the salicylate ligand were refined as disordered over two sites with occupancies of 0.581 (8 and 0.419 (8. Both disorder components of the hydroxy group form intramolecular O—H...O hydrogen bonds.

  2. Di-μ-cyanido-tetra-cyanido(5,5,7,12,12,14-hexa-methyl-1,4,8,11-tetra-aza-cyclo-tetra-decane)[N-(quinolin-8-yl)quinoline-2-carboxamidato]diiron(III)nickel(II) 2.07-hydrate.

    Science.gov (United States)

    Yang, Yuqi; Zhou, Hongbo; Shen, Xiaoping

    2013-05-01

    The asymmetric unit of the title complex, [Fe2Ni(C19H12N3O)2(CN)6(C16H36N4)]·2.07H2O, contains one [Fe(qcq)(CN)3](-) anion, half a [Ni(teta)](2+) cation and two partially occupied inter-stitial water mol-ecules [qcq(-) is the N-(quinolin-8-yl)quinoline-2-carboxamidate anion and teta is 5,5,7,12,12,14-hexa-methyl-1,4,8,11-tetra-aza-cyclo-tetra-deca-ne]. In the complex mol-ecule, two [Fe(qcq)(CN)3](-) anions additionally coordinate the central [Ni(teta)](2+) cation through cyanide groups in a trans mode, resulting in a trinuclear structure with the Ni(2+) cation lying on an inversion centre. The two inter-stitial water mol-ecules are partially occupied, with occupancy factors of 0.528 (10) and 0.506 (9). O-H⋯O and O-H⋯N hydrogen bonding involving the two lattice water molecules and the carbonyl function and a teta N atom in an adjacent cluster leads to the formation of layers extending parallel to (010).

  3. 2,3,4,6-Tetra-O-acetyl-β-d-galactopyranosyl 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl disulfide tetrahydrofuran solvate

    Directory of Open Access Journals (Sweden)

    Matías López-Rodríguez

    2008-12-01

    Full Text Available The asymmetric unit of title compound, C28H38O18S2·C4H8O, comprises one disulfide-bridged sugar molecule and one solvent molecule. No significant differences in structural parameters are found between the present structure and the previously determined unsolvated form [Brito, López-Rodríguez, Bényei & Szilagyi (2006. Carbohydr. Res. 341, 2967–2972]. The compounds are characterized by a compact structure with spatial proximity of the two pyranosyl rings. One of the carbonyl atoms is disordered over two sites [site occupancy = 0.69 (7 for major component] and the displacement parameters for the THF species are unsually large.

  4. An overview on importance, synthetic strategies and studies of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW

    Directory of Open Access Journals (Sweden)

    J. Venkata Viswanath

    2016-10-01

    Full Text Available 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (HNIW, commonly called as CL-20, is a high energy and high density material of keen interest to both commercial and scientific worlds due to its greater insensitivity (reduced sensitivity along with a positive high heat of formation, which is due to the azanitro groups attached to the skeleton of HNIW and its highly strained cage structure. It plays a remarkable role in modification and replacement of most of the propellant (gun and rocket preparations. In this report we present the comparative strategies involved in the syntheses of HNIW with respect to economical and environmental aspects. Various methods reported in the literature on the purification of the crude HNIW (α-HNIW to obtain ε-form of HNIW (high dense/more potential are consolidated. Understanding of the structure, morphology, energetics, thermal behavior and their modification to meet the applicability (decreased impact sensitivity determines the industrial application of HNIW. A compilation of the available literature on the aforementioned characteristic properties for obtaining a value added ε-HNIW is discussed here. This overview also reports the literature available on newer forms of HNIW including derivatives and cocrystals, which increase the performance of HNIW.

  5. In situ X-ray and neutron diffraction of the Ruddlesden-Popper compounds (RE2-xSrx)0.98(Fe0.8Co0.2)1-yMgyO4-δ (RE=La, Pr): Structure and CO2 stability

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Hauback, B.C.; Hendriksen, Peter Vang

    2013-01-01

    The crystal structure of the Ruddlesden-Popper compounds (La 1.0Sr1.0)0.98Fe0.8Co 0.2O4-δ and (La1.2Sr0.8) 0.98(Fe0.8Co0.2)0.8Mg 0.2O4-δ was investigated at 1000 °C in N 2 (aO2=1×10-4) by in-situ powder neutron diffraction. In-situ powder X-ray diffraction (PXD) was also employed to investigate....... The equivalent pseudo-cubic thermal and chemical expansion coefficients are in agreement with values determined by dilatometry. The chemical stability in CO2 containing environments of various Ruddlesden-Popper compounds with chemical formula (RE2-xSr x)0.98(Fe0.8Co0.2) 1-yMgyO4-δ (RE=La, Pr), as well...

  6. Magnetism of CuCl{sub 22D{sub 2}O and CuCl{sub 22H{sub 2}O, and of CuBr{sub 26H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    DeFotis, G.C., E-mail: gxdefo@wm.edu [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hampton, A.S.; Van Dongen, M.J.; Komatsu, C.H.; Benday, N.S.; Davis, C.M. [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hays, K.; Wagner, M.J. [Department of Chemistry, George Washington University, Washington, D.C. 20052 (United States)

    2017-07-15

    Highlights: • CuCl{sub 22D{sub 2}O is examined magnetically and compared with CuCl{sub 22H{sub 2}O. • Slightly lower magnetic characteristic temperatures occur for deuterated dihydrate. • The new compound CuBr{sub 26H{sub 2}O is examined magnetically. • Unexpected relationships appears between magnetic behaviors of CuBr{sub 26H{sub 2}O and CuBr{sub 2}. • Two alternative monoclinic unit cells can account for diffraction data on CuBr{sub 26H{sub 2}O. - Abstract: The magnetic properties of little examined CuCl{sub 22D{sub 2}O are studied and compared with those of CuCl{sub 22H{sub 2}O. New CuBr{sub 26H{sub 2}O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of −6.0 and −4.7 K, respectively, in χ{sub M} = C/(T − θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr{sub 2}. A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr{sub 2}, but with almost twice the magnitude. Powder X-ray diffraction data for CuBr{sub 26H{sub 2}O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

  7. Phase formation in the Li2MoO4–K2MoO4–In2(MoO4)3 system and crystal structures of new compounds K3InMo4O15 and LiK2In(MoO4)3

    International Nuclear Information System (INIS)

    Khal’baeva, Klara M.; Solodovnikov, Sergey F.; Khaikina, Elena G.; Kadyrova, Yuliya M.; Solodovnikova, Zoya A.; Basovich, Olga M.

    2012-01-01

    XRD study of solid-phase interaction in the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system was performed. The boundary K 2 MoO 4 –In 2 (MoO 4 ) 3 system is an non-quasibinary join of the K 2 O–In 2 O 3 –MoO 3 system where a new polymolybdate K 3 InMo 4 O 15 isotypic to K 3 FeMo 4 O 15 was found. In the structure (a=33.2905(8), b=5.8610(1), c=15.8967(4) Å, β=90.725(1)°, sp. gr. C2/c, Z=8, R(F)=0.0407), InO 6 octahedra, Mo 2 O 7 diortho groups and MoO 4 tetrahedra form infinite ribbons {[In(MoO 4 ) 2 (Mo 2 O 7 )] 3− } ∞ along the b-axis. Between the chains, 8- to 10-coordinate potassium cations are located. A subsolidus phase diagram of the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system was constructed and a novel triple molybdate LiK 2 In(MoO 4 ) 3 was revealed. Its crystal structure (a=7.0087(2), b=9.2269(3), c=10.1289(3) Å, β=107.401(1)°, sp. gr. P2 1 , Z=2, R(F)=0.0280) contains an open framework of vertex-shared MoO 4 tetrahedra, InO 6 octahedra and LiO 5 tetragonal pyramids with nine- and seven-coordinate potassium ions in the framework channels. - Graphical abstract: Exploring the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system showed its partial non-quasibinarity and revealed new compounds K 3 InMo 4 O 15 (isotypic to K 3 FeMo 4 O 15 ) and LiK 2 In(MoO 4 ) 3 which were structurally studied. An open framework of the latter is formed by vertex-shared MoO 4 tetrahedra, InO 6 octahedra and LiO 5 tetragonal pyramids. Highlights: ► Subsolidus phase relations in the Li 2 MoO 4 –K 2 MoO 4 –In 2 (MoO 4 ) 3 system were explored. ► The K 2 MoO 4 –In 2 (MoO 4 ) 3 system is a non-quasibinary join of the K 2 O–In 2 O 3 –MoO 3 system. ► New compounds K 3 InMo 4 O 15 and LiK 2 In(MoO 4 ) 3 were obtained and structurally studied. ► K 3 InMo 4 O 15 is isotypic to K 3 FeMo 4 O 15 and carries bands of InO 6 , MoO 4 and Mo 2 O 7 units. ► An open framework of LiK 2 In(MoO 4 ) 3 is formed by polyhedra MoO 4 , InO 6 and LiO 5 .

  8. Characterization of Li4Ti5O12 and LiMn2O4 spinel materials treated with aqueous acidic solutions

    NARCIS (Netherlands)

    Simon, D.R.

    2007-01-01

    In this thesis an investigation of two spinel materials, Li4Ti5O12 and LiMn2O4 used for Li-ion battery applications is performed interms of formation and reactivity towards acidic solutions. Subsequent characterizations such as structural, magnetic, chemical, and electrochemical characterizations

  9. Cs7Sm11[TeO3]12Cl16 and Rb7Nd11[TeO3]12Br16, the new tellurite halides of the tetragonal Rb6LiNd11[SeO3]12Cl16 structure type

    Science.gov (United States)

    Charkin, Dmitri O.; Black, Cameron; Downie, Lewis J.; Sklovsky, Dmitry E.; Berdonosov, Peter S.; Olenev, Andrei V.; Zhou, Wuzong; Lightfoot, Philip; Dolgikh, Valery A.

    2015-12-01

    Two new rare-earth - alkali - tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs7Sm11[TeO3]12Cl16 (I) and Rb7Nd11[TeO3]12Br16 (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn11(TeO3)12] and [M6X16] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted.

  10. Study of the Thermodynamics of Chromium(III) and Chromium(VI) Binding to Fe3O4 and MnFe2O4 nanoparticles

    Science.gov (United States)

    Luther, Steven; Brogfeld, Nathan; Kim, Jisoo; Parsons, J.G.

    2013-01-01

    Removal of chromium(III) or (VI) from aqueous solution was achieved using Fe3O4, and MnFe2O4 nanomaterials. The nanomaterials were synthesized using a precipitation method and characterized using XRD. The size of the nanomaterials was determined to be 22.4 ± 0.9 nm (Fe3O4) and 15.5 ± 0.5 nm (MnFe2O4). The optimal binding pH for chromium(III) and chromium(VI) were pH 6 and pH 3. Isotherm studies were performed, under light and dark conditions, to determine the capacity of the nanomaterials. The capacities for the light studies with MnFe2O4 and Fe3O4 were determined to be 7.189 and 10.63 mg/g, respectively, for chromium(III). The capacities for the light studies with MnFe2O4 and Fe3O4 were 3.21 and 3.46 mg/g, respectively, for chromium(VI). Under dark reaction conditions the binding of chromium(III) to the MnFe2O4 and Fe3O4 nanomaterials were 5.74 and 15.9 mg/g, respectively. The binding capacity for the binding of chromium(VI) to MnFe2O4 and Fe3O4 under dark reaction conditions were 3.87 and 8.54 mg/g, respectively. The thermodynamics for the reactions showed negative ΔG values, and positive ΔH values. The ΔS values were positive for the binding of chromium(III) and for chromium(VI) binding under dark reaction conditions. The ΔS values for chromium(VI) binding under the light reaction conditions were determined to be negative. PMID:23558081

  11. Oxide fluoride sulfides of the lanthanoids with the formula M{sub 6}O{sub 2}F{sub 8}S{sub 3} (M = La-Nd, Sm, Gd); Oxidfluoridsulfide der Lanthanoide vom Formeltyp M{sub 6}O{sub 2}F{sub 8}S{sub 3} (M = La-Nd, Sm, Gd)

    Energy Technology Data Exchange (ETDEWEB)

    Grossholz, Hagen; Zimmermann, Dirk D.; Janka, Oliver; Schleid, Thomas [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie

    2013-07-15

    The lanthanoid(III) oxide fluoride sulfides M{sub 6}O{sub 2}F{sub 8}S{sub 3} (M = La-Nd, Sm, Gd) can be obtained by reacting the rare-earth metals, their trifluorides and sesquioxides with elemental sulfur in appropriate molar ratios at 850 C flux-assisted by NaCl in gas-tightly sealed niobium or tantalum ampoules. All compounds are colorless, except for those containing M = Pr with green, M = Nd with lilac and M = Sm with yellow color. They form transparent single crystals as needles or rods. The M{sub 6}O{sub 2}F{sub 8}S{sub 3} representatives crystallize in a hexagonal structure (space group: P6{sub 3}/m; a {approx} 1382-1326, c {approx} 398-376 pm, c/a {approx} 0.288-0.284; Z = 2) with two different crystallographic M{sup 3+} positions. The (M2){sup 3+} cations reside in ninefold coordination of anions arranged as tricapped trigonal prisms formed by three F{sup -}, four mixed-occupied O{sup 2-}/F{sup -} and two S{sup 2-} anions, resembling the unique M{sup 3+} coordination sphere of the M{sub 3}OF{sub 5}S-type oxide fluoride sulfides. The (M1){sup 3+} cations are surrounded by square antiprisms built of four O{sup 2-}/F{sup -} and S{sup 2-} anions each, which are capped by one F{sup -} anion each, again resulting in a ninefold coordination similar to that of the A-MFS-type fluoride sulfides. While the crystallographically unique S{sup 2-} anions have six cationic neighbors arranged in trigonal prisms, there are four different light-anion positions. Two of them, representing only fluoride anions, are situated in a triangular environment of cations ((F1){sup -}: planar, (F2){sup -}: non-planar). The mixed-occupied light-anion positions (F3){sup -}/(O3){sup 2-} and (F4){sup -}/(O4){sup 2-} exhibit tetrahedral coordination spheres with a ratio F{sup -}: O{sup 2-} = 2:1. The M{sub 6}O{sub 2}F{sub 8}S{sub 3} arrangement is characterized by an empty hexagonal channel structure created by (F1){sup -} anions with a potential of accommodating alkali-metal cations like Na

  12. (2E-3-(6-Chloro-2-methoxyquinolin-3-yl-1-(2-methyl-4-phenylquinolin-3-ylprop-2-en-1-one acetone monosolvate

    Directory of Open Access Journals (Sweden)

    Edward R. T. Tiekink

    2013-08-01

    Full Text Available In the title solvate, C29H21ClN2O2·C3H6O, a prop-2-en-1-one bridge links two quinolinyl residues; the latter are almost perpendicular [dihedral angle = 78.27 (6°]. The dihedral angle between the quinonyl ring system and its pendant phenyl group is 59.78 (8°. A small twist in the bridging prop-2-en-1-one group is noted [O=C—C=C torsion angle = −10.6 (3°]. In the crystal, a three-dimensional architecture arises as a result of C—H...O and π–π stacking [centroid–centroid distances = 3.5504 (12–3.6623 (12 Å].

  13. Di-μ-chlorido-bis({4-[bis(trimethylsilylamino]-6-chloro-2,2,8,8-tetramethyl-5,7-bis(trimethylsilyl-3,5,7-triaza-4,6-diphospha-2,8-disilanon-3-en-4-ido-κ2P,P′}palladium(II diethyl ether disolvate

    Directory of Open Access Journals (Sweden)

    Martha Höhne

    2016-06-01

    Full Text Available The title compound, [Pd2(C18H54Cl2N4P2Si62Cl22C4H10O, features a dinuclear chloride-bridged palladium complex bearing two equivalents of the novel monoanionic mixed valent (λ3-P—N—(λ5-P ligand. A metal catalyzed coupling of two aminoiminophosphines and a shift of one chlorine from the metal to the phosphorus results in the (λ3-P—N—(λ5-P ligand. The molecule contains a planar bimetallic Pd2Cl2 core with a crystallographic centre of inversion at the mid-point of the Pd...Pd line. The Pd atoms are in a distorted square-planar arrangement, where the P/Pd/P and Cl/Pd/Cl planes are twisted with respect to each other by a dihedral angle of 7.57 (4°. The P—Pd—P bite angle is 71.380 (18°. Intramolecular C—H...Cl interactions are observed. In the crystal, the diethyl ether solvent molecule is disordered over two sites, with an occupancy ratio of 0.788 (5:0.212 (5.

  14. Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H2O)2SO4 and Cu(tn)Cl2

    International Nuclear Information System (INIS)

    Baranová, Lucia; Orendáčová, Alžbeta; Čižmár, Erik; Tarasenko, Róbert; Tkáč, Vladimír; Orendáč, Martin; Feher, Alexander

    2016-01-01

    Organo-metallic compounds Cu(en)(H 2 O) 2 SO 4 (en=C 2 H 8 N 2 ) and Cu(tn)Cl 2 (tn=C 3 H 10 N 2 ) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k B ≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H 2 O) 2 SO 4 at T C =0.9 K while hidden in Cu(tn)Cl 2 . A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H 2 O) 2 SO 4 (1) and Cu(tn)Cl 2 (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.

  15. Structure of cerium-manganese pivalates

    International Nuclear Information System (INIS)

    Romanenko, G.V.; Fursova, E.Yu.; Ovcharenko, V.I.

    2009-01-01

    Formation of Ce, Mn-varied metal polynuclear compounds [Ce 3 Mn 6 (O) 5 (OH) 3 Piv 12 Cl 2 (THF) 3 ]·2THF, [Ce 3 Mn 8 (O) 8 Piv 16 C1 2 (HPiv) 2 ]·C 7 H 16 , [Ce 10 Mn 4 (O) 6 (OH) 12 Piv 16 C1 2 (THF) 22THF·2H 2 O, [CeMn 11 C1 3 (O) 8 Piv 15 (H 2 O)]·CH 2 C1 2 , [CeMn 8 (O) 8 Piv 12 (HPiv) 2 (THF) 2 ] has been recorded, their structures have been studied. Reaction of [Ce 3 Mn 6 (O) 5 (OH) 3 Piv 12 C1 2 (THF) 3 ]·2THF with nitronyl-nitroxyl radicals (NIT-R-2-R-tetramethyl-2-imidazoline-3-oxide-1-oxyl, R=Me, p-Py) demonstrates the possibility of synthesis of p,d,f-heterospin complexes. It realises due to the substitution of THF coordinated molecules by nitroxyl molecules. X-ray structure study of these complexes is pointed that [Ce 3 Mn 6 (O) 5 (OH) 3 Piv 12 Cl 2 (HPiv)(NIT-Me) 2 ] and [CeMn 8 (O) 8 Piv 12 (NIT-p-Py) 42C 6 H 14 have a molecular structure, [Ce 3 Mn 6 (O) 5 (OH) 3 Piv 12 Cl 2 (NIT-Me)(H 2 O)] - chain structure

  16. Structure of Chloro bis(1,10-phenanthroline)Cobalt(II) Complex, [Co(phen)2(Cl)(H2O)]Cl · 2H2O

    International Nuclear Information System (INIS)

    Zhao, Pu Su; Lu, Lu De; Jian, Fang Fang

    2003-01-01

    The crystal structure of [Co(phen) 2 (Cl)(H 2 O)] Cl · 2H 2 O(phen=1,10-phenanthroline) has been determined by X-ray crystallography. It crystallizes in the triclinic system, space group P 1 , with lattice parameters a=9.662(2), b=11.445(1), c=13.037(2)A, α=64.02(1), β=86.364(9), γ=78.58(2) .deg., and Z=2. The coordinated cations contain a six-coordinated cobalt atom chelated by two phen ligands and one chloride anion and one water ligand in cis arrangement. In addition to the chloride coordinated to the cobalt, there are one chloride ion and four water molecules which complete the crystal structure. In the solid state, the title compound forms three dimensional network structure through hydrogen bonds, within which exists the strongest hydrogen bond (O(3)-O(4)=2.33A). The intermolecular hydrogen bonds connect the [Co(phen) 2 (Cl)(H 2 O)] 1+ , H 2 O moieties and chloride ion

  17. Two new coordination polymers constructed by naphthalene-1,4-dicarboxylic acid and 2,4-diamino-6-methyl-triazine

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yamin, E-mail: liyamin@henu.edu.cn [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Xiao, Changyu [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Zhang, Xudong [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Xu, Yanhui [Department of Medical Imaging, Bethune Medical Non-Commissioned Officer' s, College, Shijiazhuang, Hebei 050081 (China); Li, Junrui; Lun, Huijie; Chen, Qi [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China)

    2013-08-15

    Two new transition metal coordination complexes, ([MnO(nda)](H{sub 2}dmt)(H{sub 2}O)){sub n} (1), [Ag{sub 5}(nda){sub 2.5}(dmt)]{sub n} (2), (H{sub 2}nda=naphthalene-1,4-dicarboxylic acid, dmt=2,4-diamine-6-methyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of H{sub 2}nda and dmt with the homologous MnCl{sub 24H{sub 2}O and AgNO{sub 3}, respectively, and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The compound 1 exhibits a 3D network comprising 1D metal chain (MnO(CO{sub 2}){sub 2}){sub n} connected by the ligand nda{sup 2−}, featuring a four-connected uninodal diamond -like topology. In compound 2, it is firstly observed that decanuclear silver units as secondary building units to construct 3D network by the ligands dmt and nda{sup 2−}, with a rare 2-nodal (3,8)-connected tfz-d topology ((4{sup 3}){sub 2}(4{sup 6}.6{sup 18}.8{sup 4})). The interactions within each Mn(II)—Mn(II) pair of compound 1 are antiferromagnetic (g=2.07, J=−1.42(1) cm{sup −1}, zj′=−0.73(2) cm{sup −1}). In addition, compound 2 exhibits photoluminescent property at about 472 nm (λ{sub ex}=394 nm). - Graphical abstract: Two new transition metal coordination complexes 1–2 have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis thermogravimetric analysis (TGA). Highlights: • The compound 1 exhibits a 3D network with four-connected uninodal diamond-like topology. • The first 3D network of 2 with a rare tfz-d topology consists of decanuclear silver clusters as secondary building units. • The magnetic measurement indicates the compound 1 shows antiferromagnetic interactions. • The photoluminescent property of 2 has been measured.

  18. Crystal structure of (1R,2S,4R,7R,8S,9R-3,3-dichloro-8,9-epoxy-4,8,12,12-tetramethyltricyclo[5.5.0.02,4]dodecane

    Directory of Open Access Journals (Sweden)

    Ahmed Benzalim

    2015-08-01

    Full Text Available The title compound, C16H24Cl2O, is built up from two fused six- and seven-membered rings which bear a dichlorocyclopropane group and an epoxy group, respectively. In the molecule, the six-membered ring adopts an envelope configuration with the C atom linking the epoxy ring at the flap, while the seven-membered ring adopts a boat–sofa conformation.

  19. High-Pressure Synthesis and Characterization of the Ammonium Yttrium Borate (NH4)YB8O14.

    Science.gov (United States)

    Schmitt, Martin K; Podewitz, Maren; Liedl, Klaus R; Huppertz, Hubert

    2017-11-20

    The first high-pressure yttrium borate (NH 4 )YB 8 O 14 was synthesized at 12.8 GPa/1300 °C using a Walker-type multianvil module. The compound crystallizes in the orthorhombic space group Pnma (no. 62) with the lattice parameters a = 17.6375(9), b = 10.7160(5), and c = 4.2191(2) Å. (NH 4 )YB 8 O 14 constitutes a novel structure type but exhibits similarities to the crystal structure of β-BaB 4 O 7 . X-ray single-crystal and powder diffraction, EDX, vibrational spectroscopy as well as quantum chemical calculations were used to characterize (NH 4 )YB 8 O 14 .

  20. Porous Hollow Superlattice NiMn2O4/NiCo2O4 Mesocrystals as a Highly Reversible Anode Material for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Lingjun Li

    2018-05-01

    Full Text Available As a promising high-capacity anode material for Li-ion batteries, NiMn2O4 always suffers from the poor intrinsic conductivity and the architectural collapse originating from the volume expansion during cycle. Herein, a combined structure and architecture modulation is proposed to tackle concurrently the two handicaps, via a facile and well-controlled solvothermal approach to synthesize NiMn2O4/NiCo2O4 mesocrystals with superlattice structure and hollow multi-porous architecture. It is demonstrated that the obtained NiCo1.5Mn0.5O4 sample is made up of a new mixed-phase NiMn2O4/NiCo2O4 compound system, with a high charge capacity of 532.2 mAh g−1 with 90.4% capacity retention after 100 cycles at a current density of 1 A g−1. The enhanced electrochemical performance can be attributed to the synergistic effects of the superlattice structure and the hollow multi-porous architecture of the NiMn2O4/NiCo2O4 compound. The superlattice structure can improve ionic conductivity to enhance charge transport kinetics of the bulk material, while the hollow multi-porous architecture can provide enough void spaces to alleviate the architectural change during cycling, and shorten the lithium ions diffusion and electron-transportation distances.

  1. Giant room-temperature magnetoresistance in La{sub 0.8}Tb{sub 0.2}MnO{sub 3} under the low magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yingtang [Physics of Department, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080 (China); School of Material Science and Engineering, Shaanxi University of Technology, Hanzhong 723003 (China)], E-mail: zhangyingtang76@sina.com; Chen Ziyu [Physics of Department, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)], E-mail: chenzy@buaa.edu.cn; Wang Chunchang; Jie Qiu; Lue Huibin [Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2009-05-15

    Polycrystalline perovskite La{sub 0.8}Tb{sub 0.2}MnO{sub 3} (LTMO) with an orthorhombic phase was synthesized by conventional solid-state reaction. The magnetic and electric properties of La{sub 0.8}Tb{sub 0.2}MnO{sub 3} were examined. The striking finding is that the material exhibits giant magnetoresistance at room temperature as high as -31.8% and -35.7% under the low magnetic fields of 100 and 1000 Oe, respectively. This result suggests that La{sub 0.8}Tb{sub 0.2}MnO{sub 3} has a promising potential in future device developments.

  2. Hydrothermal synthesis and crystal structures of Na{sub 2}Be{sub 3}(SeO{sub 3}){sub 4}.H{sub 2}O and Cs{sub 2}[Mg(H{sub 2}O){sub 6}]{sub 3}(SeO{sub 3}){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chen; Mei, Dajiang; Sun, Chuanling; Liu, Yunsheng; Wu, Yuandong [College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science (China)

    2017-09-04

    The selenites, Na{sub 2}Be{sub 3}(SeO{sub 3}){sub 4}.H{sub 2}O and Cs{sub 2}[Mg(H{sub 2}O){sub 6}]{sub 3}(SeO{sub 3}){sub 4}, were synthesized under hydrothermal conditions. The crystal structures of Na{sub 2}Be{sub 3}(SeO{sub 3}){sub 4}.H{sub 2}O and Cs{sub 2}[Mg(H{sub 2}O){sub 6}]{sub 3}(SeO{sub 3}){sub 4} were determined by single-crystal X-ray diffractions. Na{sub 2}Be{sub 3}(SeO{sub 3}){sub 4}.H{sub 2}O crystallizes in the triclinic space group P1 (no. 2) with unit cell parameters a = 4.8493(9), b = 12.013(2), c = 12.077(2) Aa, and Z = 2, whereas Cs{sub 2}[Mg(H{sub 2}O){sub 6}]{sub 3}(SeO{sub 3}){sub 4} crystallizes in the monoclinic space group C2/m (no. 12) with lattice cell parameters a = 12.596(6), b = 7.297(4), c = 16.914(8) Aa, and Z = 2. Na{sub 2}Be{sub 3}(SeO{sub 3}){sub 4}.H{sub 2}O features a three-dimensional open framework structure formed by BeO{sub 4} tetrahedra and SeO{sub 3} trigonal pyramids. Na cations and H{sub 2}O molecules are located in different tunnels. Cs{sub 2}[Mg(H{sub 2}O){sub 6}]{sub 3}(SeO{sub 3}){sub 4} has a structure composed of isolated [Mg(H{sub 2}O){sub 6}] octahedra and SeO{sub 3} trigonal pyramids interacted by hydrogen bonds, and Cs cations are resided in-between. Both compounds were characterized by thermogravimetric analysis and FT-IR spectroscopy. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Standarization of Mn-54 by liquid scintillation counting using organic samples of (C8H15 O2)2 Mn-54

    International Nuclear Information System (INIS)

    1990-01-01

    A new method of standardization of Mn 54 by liquid scintillation counting with an organic sample of (C 8 H 15 O 2 ) 2 Mn 54 is described. This procedure shows a good long term stability of samples, over 20 days, and counting efficiencies between 10% and 24% for PCS e INSTAGEL and 10% 32% for a toluene-based scintillator. The discrepancies between experimental and computed values are less that 0,9% for PCS and INSTAGEL and less than 1,2% for Toluene, in the 5-2,5 interval of quenching parameter. The global uncertainty on the activity concentrat-ion of a sample standardized by this method has been lower than 3% (Author)

  4. Experimental studies on cycling stable characteristics of inorganic phase change material CaCl2·6H2O-MgCl2·6H2O modified with SrCl2·6H2O and CMC

    Science.gov (United States)

    He, Meizhi; Yang, Luwei; Zhang, Zhentao

    2018-01-01

    By means of mass ratio method, binary eutectic hydrated salts inorganic phase change thermal energy storage system CaCl2·6H2O-20wt% MgCl2·6H2O was prepared, and through adding nucleating agent 1wt% SrCl2·6H2O and thickening agent 0.5wt% carboxy methyl cellulose (CMC), inoganic phase change material (PCM) modified was obtained. With recording cooling-melting curves simultaneously, this PCM was frozen and melted for 100 cycles under programmable temperature control. After per 10 cycles, the PCM was charaterized by differential scanning calorimeter (DSC), X-ray diffraction (XRD) and density meter, then analysing variation characteristics of phase change temperature, supercooling degree, superheat degree, latent heat, crystal structure and density with the increase of cycle index. The results showed that the average values of average phase change temperature for cooling and heating process were 25.70°C and 27.39°C respectively with small changes. The average values of average supercooling and superheat degree were 0.59°C and 0.49°C respectively, and the maximum value was 1.10°C. The average value and standard deviation of latent heat of fusion were 120.62 J/g and 1.90 J/g respectively. Non-molten white solid sediments resulted from phase separation were tachyhydrite (CaMg2Cl6·12H2O), which was characterized by XRD. Measuring density of the PCM after per 10 cycles, and the results suggested that the total mass of tachyhydrite was limited. In summary, such modified inoganic PCM CaCl2·6H2O-20wt% MgCl2·6H2O-1wt% SrCl2·6H2O-0.5wt% CMC could stay excellent circulation stability within 100 cycles, and providing reference value in practical use.

  5. Poly[diaqua(μ-4,4′-bipyridine-κ2N:N′[μ-2,2′-(p-phenylenedioxydiacetato-κ2O:O′]cadmium

    Directory of Open Access Journals (Sweden)

    Guang-Yin Wang

    2011-09-01

    Full Text Available In the title compound, [Cd(C10H8O6(C10H8N2(H2O2]n, the CdII ion has inversion symmetry and is coordinated by O atoms from two water molecules and two bridging 2,2′-(μ-p-phenylenedioxydiacetate ligands and two N atoms from two 4,4′-bipyridine ligands, giving a slightly distorted octahedral geometry. The diacetate and 4,4′-bipyridine ligands also lie across inversion centers. The bridging ligands form layers parallel to (11overline{1}, with adjacent layers interconnected via O—H...O hydrogen bonds between the coordinated water molecules and the carboxylate O atoms, giving a three-dimensional supramolecular architecture.

  6. First investigations on the quaternary system Na2O-K2O-CaO-SiO2: synthesis and crystal structure of the mixed alkali calcium silicate K1.08Na0.92Ca6Si4O15

    Science.gov (United States)

    Kahlenberg, Volker; Mayerl, Michael Jean-Philippe; Schmidmair, Daniela; Krüger, Hannes; Tribus, Martina

    2018-04-01

    In the course of an exploratory study on the quaternary system Na2O-K2O-CaO-SiO2 single crystals of the first anhydrous sodium potassium calcium silicate have been obtained from slow cooling of a melt in the range between 1250 and 1050 °C. Electron probe micro analysis suggested the following idealized molar ratios of the oxides for the novel compound: K2O:Na2O:CaO:SiO2 = 1:1:12:8 (or KNaCa6Si4O15). Single-crystal diffraction measurements on a crystal with chemical composition K1.08Na0.92Ca6Si4O15 resulted in the following basic crystallographic data: monoclinic symmetry, space group P 21/ c, a = 8.9618(9) Å, b = 7.3594(6) Å, c = 11.2453(11) Å, β= 107.54(1)°, V = 707.2(1) Å3, Z = 2. Structure solution was performed using direct methods. The final least-squares refinement converged at a residual of R(|F|) = 0.0346 for 1288 independent reflections and 125 parameters. From a structural point of view, K1.08Na0.92Ca6Si4O15 belongs to the group of mixed-anion silicates containing [Si2O7]- and [SiO4]-units in the ratio 1:2. The mono- and divalent cations occupy a total of four crystallographically independent positions located in voids between the tetrahedra. Three of these sites are exclusively occupied by calcium. The fourth site is occupied by 54(1)% K and 46%(1) Na, respectively. Alternatively, the structure can be described as a heteropolyhedral framework based on corner-sharing silicate tetrahedra and [CaO6]-octahedra. The network can build up from kröhnkite-like [Ca(SiO4)2O2]-chains running along [001]. A detailed comparison with other A2B6Si4O15-compounds including topological and group-theoretical aspects is presented.

  7. New perovskite-based manganite Pb2Mn2O5

    International Nuclear Information System (INIS)

    Hadermann, Joke; Abakumov, Artem M.; Perkisas, Tyche; D'Hondt, Hans; Tan Haiyan; Verbeeck, Johan; Filonenko, Vladimir P.; Antipov, Evgeny V.; Van Tendeloo, Gustaaf

    2010-01-01

    A new perovskite based compound Pb 2 Mn 2 O 5 has been synthesized using a high pressure high temperature technique. The structure model of Pb 2 Mn 2 O 5 is proposed based on electron diffraction, high angle annular dark field scanning transmission electron microscopy and high resolution transmission electron microscopy. The compound crystallizes in an orthorhombic unit cell with parameters a=5.736(1) A∼√2a p , b=3.800(1) A∼a p , c=21.562(6) A∼42a p (a p -the parameter of the perovskite subcell) and space group Pnma. The Pb 2 Mn 2 O 5 structure consists of quasi two-dimensional perovskite blocks separated by 1/2[110] p (101) p crystallographic shear planes. The blocks are connected to each other by chains of edge-sharing MnO 5 distorted tetragonal pyramids. The chains of MnO 5 pyramids and the MnO 6 octahedra of the perovskite blocks delimit six-sided tunnels accommodating double chains of Pb atoms. The tunnels and pyramidal chains adopt two mirror-related configurations ('left' L and 'right' R) and layers consisting of chains and tunnels of the same configuration alternate in the structure according to an -L-R-L-R-sequence. The sequence is sometimes locally violated by the appearance of -L-L- or -R-R-fragments. A scheme is proposed with a Jahn-Teller distortion of the MnO 6 octahedra with two long and two short bonds lying in the a-c plane, along two perpendicular orientations within this plane, forming a d-type pattern. - Graphical abstract: Order of the Jahn-Teller distorted MnO 6 octahedra in Pb 2 Mn 2 O 5 . Two long and two short bonds lie in the a-c plane, along two perpendicular orientations within this plane, forming a d-type pattern.

  8. Bis(2,6-dimethylanilinium diaquabis(dihydrogen diphosphato-κ2O,O′cobaltate(II

    Directory of Open Access Journals (Sweden)

    Ahlem Ben Saad

    2014-03-01

    Full Text Available In the title compound, (C8H12N2[Co(H2P2O72(H2O2], the Co2+ ion lies on a crystallographic inversion centre and adopts a slightly distorted octahedral CoO6 coordination geometry arising from two chelating diphosphate [H2P2O7]2− ligands and two trans water molecules. In the crystal, the components are linked by O—H...O, N—H...O and C—H...O hydrogen bonds and weak aromatic π–π stacking [shortest centroid–centroid separation = 3.778 (2 Å] interactions. (001 layers of alternating organic cations and complex inorganic anions are apparent.

  9. The application of DTA and TG methods to investigate the non-crystalline hydration products of CaAl2O4 and Ca7ZrAl6O18 compounds

    International Nuclear Information System (INIS)

    Szczerba, Jacek; Madej, Dominika; Śnieżek, Edyta; Prorok, Ryszard

    2013-01-01

    Highlights: ► Hydrates, i.e. CAH 10 , C 2 AH 8 , C 3 AH 6 and C 4 AH 19 are formed during hydration of CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 . ► Hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds were investigated by X-ray diffraction, SEM/EDS and thermal analysis. ► The hydration reaction proceeds as consumes the unreacted core of the CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 grain. - Abstract: The hydration products and thermal decomposition mechanism of hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds were investigated by X-ray diffraction, SEM/EDS and thermal analysis. The processes of crystal hydrate nucleation and precipitation were preceded by the evolution of the X-ray amorphous phase during the first 24 h of hydration. DTA–TGA–EGA techniques allowed the study of the detailed decomposition and identification of intermediate and stable to be performed. The differential thermal analysis (DTA) curves of hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds show five similar endothermic peaks due to crystal water desorption. According to the quantitative TGA–EGA analyses performed on hydrated CaAl 2 O 4 and Ca 7 ZrAl 6 O 18 compounds, it was found that C 2 AH 8 , C 3 AH 6 and Al(OH) 3 phases are the main hydration products of CaAl 2 O 4 . Under the same laboratory conditions, the hydration of Ca 7 ZrAl 6 O 18 proceeds with the formation of mainly CAH 10 and AH 3 -gel phases. We provide the original illustrations of the hydrate crystals formation via amorphous phases

  10. 1D and 3D Polymeric Manganese(II) Thiolato Complexes: Synthesis, Structure, and Properties of    ∞3[Mn4(SPh)8] and ∞1[Mn(SMes)2].

    Science.gov (United States)

    Eichhöfer, Andreas; Lebedkin, Sergei

    2018-01-16

    Reactions of [Mn{N(SiMe 3 ) 2 } 2 ] 2 with 2.1 equiv of RSH, R = Ph or Mes = C 6 H 2 -2,4,6-(CH 3 ) 3 , yield compounds of the formal composition "Mn(SR) 2 ". Single-crystal X-ray diffraction reveals that ∞ 1 [Mn(SMes) 2 ] forms one-dimensional chains in the crystal via μ 2 -SMes bridges, whereas ∞ 3 [Mn 4 (SPh) 8 ] comprises a three-dimensional network in which adamantanoid cages composed of four Mn atoms and six μ 2 -bridging SPh ligands are connected in three dimensions by doubly bridging SPh ligands. Thermogravimetric analysis and powder diffractometry indicate an reversible uptake of solvent molecules (tetrahydrofuran) into the channels of ∞ 1 [Mn(SMes) 2 ]. Magnetic measurements reveal antiferromagnetic coupling for both compounds with J = -8.2 cm -1 ( ∞ 1 [Mn(SMes) 2 ]) and -10.0 cm -1 ( ∞ 3 [Mn 4 (SPh) 8 ]), respectively. Their optical absorption and photoluminescence (PL) excitation spectra display characteristic d-d bands of Mn 2+ ions in the visible spectral region. Both compounds emit bright phosphorescence at ∼800 nm at low temperatures (SMes) 2 ] retains a moderately intense emission at ambient temperature (with a quantum yield of 1.2%). Similar PL properties are also found for the related selenolate complexes ∞ 1 [Mn(SeR) 2 ] (R = Ph, Mes).

  11. Synthesis of ceramic powders of La9,56 (SiO4)6O2,34 and La9,8Si5,7MgO,3O26,4 by modified sol-gel process

    International Nuclear Information System (INIS)

    Lira, Sabrina Lopes; Paiva, Mayara Rafaela Soares; Misso, Agatha Matos; Elias, Daniel Ricco; Yamagata, Chieko

    2012-01-01

    Lanthanum silicate oxyapatite materials are promising for application as electrolyte in solid oxide fuel cells because of high ionic conductivity at temperatures between 600 deg C and 800 deg C. In this work, oxyapatites with the composition La 9,56 (SiO 4 ) 6 O 2,34 , and La 9,8 Si 5,7 Mg 0,3 O 26,4 were synthesized by using the sol-gel method, followed by precipitation. Initially, the gel of silica was synthesized from sodium silicate solution, by acid catalysis using lanthanum and magnesium chloride solution. Then, the La and Mg hydroxides were precipitated with NaOH in the gel. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and measurements of specific surface area. The crystalline oxyapatite phase of La 9,56 (SiO 4 ) 6 O 2,34 , and was La 9,8 Si 5,7 Mg 0,3 O 26,4 obtained by calcination at 900 deg C for 2 and 1h respectively (author)

  12. 4-(2,4-Dichlorophenyl-2-(1H-indol-3-yl-6-methoxypyridine-3,5-dicarbonitrile

    Directory of Open Access Journals (Sweden)

    M. N. Ponnuswamy

    2008-10-01

    Full Text Available In the title compound, C22H12Cl2N4O, the indole ring system and the benzene ring form dihedral angles of 21.18 (7° and 68.43 (8°, respectively, with the pyridine ring. The methoxy group is coplanar with the pyridine ring. In the crystal structure N—H...N intermolecular hydrogen bonds link the molecules into C(10 chains running along [011]. Intramolecular C—H...N hydrogen bonds are also observed.

  13. Preparation and characterization of a layered perovskite-type organic-inorganic hybrid compound (C8NH6-CH2CH2NH3)2CuCl4

    International Nuclear Information System (INIS)

    Zheng Yingying; Wu Gang; Deng Meng; Chen Hongzheng; Wang Mang; Tang, B.-Z.

    2006-01-01

    The organic-inorganic hybrid compound (C 8 NH 6 -CH 2 CH 2 NH 3 ) 2 CuCl 4 (AEI-CuCl 4 ) was synthesized from ethanol solution containing copper chloride and 3-2-(aminoethyl) indole hydrochloride (AEI-HCl). High order diffraction peaks corresponding to (0 0 l; l = 2, 4, 6, ...) observed in the X-ray diffraction profile of AEI-CuCl 4 indicated the formation of hybrid crystal with layered perovskite structure. The organic-inorganic hybrid crystal thin film can be easily prepared by spin-coating method from the ethanol solution of the AEI-CuCl 4 perovskite and it showed characteristic absorptions of CuCl-based layered perovskite centered at 288 and 388 nm, as well as the photoluminescence peak at around 420 nm. The unaided-eye-detectable blue fluorescence emission comes from the cooperation of AEI-HCl and AEI-CuCl 4 perovskite, in which protonized aminoethyl indole dominates the shape of the spectrum and the enhancement of emission intensity is due to the formation of the perovskite structure. The thermal analysis presented that the AEI-CuCl 4 perovskite started to melt at 182 deg. C, together with the beginning of the decomposition of the hybrids. Compared with the organic-inorganic perovskite hybrids reported previously, the AEI-CuCl 4 perovskite shows a novel stepwise decomposition behavior

  14. Bromine-rich Zinc Bromides: Zn6Br12(18-crown-6)2×(Br2)5, Zn4Br8(18-crown-6)2×(Br2)3, and Zn6Br12(18-crown-6)2×(Br2)2.

    Science.gov (United States)

    Hausmann, David; Feldmann, Claus

    2016-06-20

    The bromine-rich zinc bromides Zn6Br12(18-crown-6)2×(Br2)5 (1), Zn4Br8(18-crown-6)2×(Br2)3 (2), and Zn6Br12(18-crown-6)2×(Br2)2 (3) are prepared by reaction of ZnBr2, 18-crown-6, and elemental bromine in the ionic liquid [MeBu3N][N(Tf)2] (N(Tf)2 = bis(trifluoromethylsulfonyl)amide). Zn6Br12(18-crown-6)2×(Br2)5 (1) is formed instantaneously by the reaction. Even at room temperature, compound 1 releases bromine, which was confirmed by thermogravimetry (TG) and mass spectrometry (MS). The release of Br2 can also be directly followed by the color and density of the title compounds. With controlled conditions (2 weeks, 25 °C, absence of excess Br2) Zn6Br12(18-crown-6)2×(Br2)5 (1) slowly releases bromine with conconcurrent generation of Zn4Br8(18-crown-6)2×(Br2)3 (2) (in ionic liquid) and Zn6Br12(18-crown-6)2×(Br2)2 (3) (in inert oil). All bromine-rich zinc bromides contain voluminous uncharged (e.g., Zn3Br6(18-crown-6), Zn2Br4(18-crown-6)) or ionic (e.g., [Zn2Br3(18-crown-6)](+), [(Zn2Br6)×(Br2)2](2-)) building units with dibromine molecules between the Zn oligomers and partially interconnecting the Zn-containing building units. Due to the structural similarity, the bromine release is possible via crystal-to-crystal transformation with retention of the crystal shape.

  15. Crystal structure of (1S,3R,8R,9R-2,2-dichloro-3,7,7-trimethyl-10-methylenetricyclo[6.4.0.01,3]dodecan-9-ol

    Directory of Open Access Journals (Sweden)

    Ahmed Benzalim

    2016-08-01

    Full Text Available The title compound, C16H24Cl2O, was synthesized by treating (1S,3R,8S,9R,10S-2,2-dichloro-3,7,7,10-tetramethyl-9,10-epoxytricyclo[6.4.0.01,3]dodecane with a concentrated solution of hydrobromic acid. It is built up from three fused rings: a cycloheptane ring, a cyclohexyl ring bearing alkene and hydroxy substituents, and a cyclopropane ring bearing two chlorine atoms. The asymmetric unit contains two molecules linked by an O—H...O hydrogen bond. In the crystal, further O—H...O hydrogen bonds build up an R44(8 cyclic tetramer. One of the molecules presents disorder that affects the seven-membered ring. In both molecules, the six-membered rings display a chair conformation, whereas the seven-membered rings display conformations intermediate between boat and twist-boat for the non-disordered molecule and either a chair or boat and twist-boat for the disordered molecule owing to the disorder. The absolute configuration for both molecules is 1S,3R,8R,9R and was deduced from the chemical pathway and further confirmed by the X-ray structural analysis.

  16. Microwave properties of La{sub 0.8}Ag{sub 0.2}MnO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rostamnejadi, Ali [Malek Ashtar University of Technology, Electroceram Research Center, Shahin Shahr, Isfahan (Iran, Islamic Republic of)

    2016-11-15

    In this research, single-phase nanoparticles of La{sub 0.8}Ag{sub 0.2}MnO{sub 3} with mean particle size of 15 nm have been synthesized by sol-gel method. The microwave properties of La{sub 0.8}Ag{sub 0.2}MnO{sub 3}/paraffin nanocomposite are studied by measuring the complex permittivity and permeability in the frequency range of 1-18 GHz. The composite shows both reflection and absorption electromagnetic shielding effectiveness with maximum total value of 36 dB, which is suitable for defense and microwave radiation shielding applications at high temperatures. The electromagnetic absorption properties are described in terms of dielectric relaxation processes. (orig.)

  17. Synthesis of ZrO2-8%CeO2 and ZrO2-8%Y2O3 by polymeric precursors route

    International Nuclear Information System (INIS)

    Macedo, D.A.; Macedo, M.C.; Melo, D.M.A.; Nascimento, R.M.; Rabelo, A.A.

    2006-01-01

    The stabilization of zirconia in the cubical and tetragonal structures comes gaining importance because of its excellent thermal stability, chemical resistance, mechanical properties and oxygen conductivity. Its main applications include electrolytes of high temperature fuel cells, sensors of oxygen and electrochemical reactors. In this work the polymeric precursors route was used to synthesize ZrO 2 -8 mol% Y 2 O 3 and ZrO 2 -8 mol%CeO 2 . In this process the dopant concentration, besides making possible the stabilization of distinct structures, influences in the morphologic characteristics of the powders synthesized. The characterization of the powders was carried through X-ray diffraction for existing phases verification and average crystallite size, thermogravimetric analysis, specific surface area measures, particles size distribution by laser scattering and the powder morphology was observed using scanning electronic microscopy. The powder only calcined at 700 deg C had presented of average crystallite size of 6,77 nm for ZrO 2 -8%Y 2 O 3 and 7,14 nm for ZrO 2 -CeO 2 . (author)

  18. Trapping {BW12}2 tungstoborate: synthesis and crystal structure of hybrid [{(H2BW12O42)2O}{Mo6O6S6(OH)4(H2O)2}]14- anion.

    Science.gov (United States)

    Korenev, V S; Abramov, P A; Vicent, C; Mainichev, D A; Floquet, S; Cadot, E; Sokolov, M N; Fedin, V P

    2012-12-28

    Reaction between monolacunary {BW(11)} tungstoborate and oxothiocationic building block, {Mo(2)O(2)S(2)}, results in the formation of a new polyoxothiometalate with a unique architecture in which two [H(2)BW(12)O(43)](9-) tungstoborate subunits are linked together with a hexamolybdate [Mo(V)(6)O(6)S(6)(OH)(4)(H(2)O)(2)](2+) bridge.

  19. Ordered perovskites with cationic vacancies. 9. Compounds of the type Sr/sub 2/Srsub(1/4)Bsub(1/2)sup(III)vacantsub(1/4)WO/sub 6/ equivalent to Sr/sub 8/SrB/sub 2/sup(III)vacantW/sub 4/O/sub 24/ (Bsup(III) = La, Pr, Nd, Sm - Tm, Y)

    Energy Technology Data Exchange (ETDEWEB)

    Kemmler-Sack, S; Ehmann, A [Tuebingen Univ. (Germany, F.R.). Lehrstuhl fuer Anorganische Chemie 2

    1981-08-01

    The compounds Sr/sub 2/Srsub(1/4)Bsub(1/2)sup(III)vacantsub(1/4)WO/sub 6/ equivalent to Sr/sub 8/SrB/sub 2/sup(III)vacantW/sub 4/O/sub 24/ belong to the group of perovskites with octahedral cationic vacancies (cation/vacancy ratio (CN 6) = 7:1). For the larger Bsup(III) ions (La, Pr, Nd, Sm-Dy) different ordering effects are observed. The perovskites with Bsup(III) = Sm, Eu, Gd are polymorphic too (HT modification: higher ordered cubic perovskite (Bsup(III) = Gd: a = 2 x 8.23/sub 4/ A); LT modification: hexagonal perovskite stacking polytype (Bsup(III) = Gd: a = 9.95/sub 4/ A; c = 19.0/sub 4/ A)). With the smaller Bsup(III) ions (Ho, Er, Tm and Y) a cubic, 1:1 ordered perovskite type is observed.

  20. Four new dysprosium and neodymium octamolybdate hydrates: assembly of RE2(Mo8O27) sheets and topotactic transformations.

    Science.gov (United States)

    Kuang, Xiaojun; Evans, Ivana R

    2010-07-05

    Four new Dy and Nd hydrated octamolybdate materials have been prepared: [Dy(2)(H(2)O)(12)](Mo(8)O(27)) x 8 H(2)O, [Dy(2)(H(2)O)(6)](Mo(8)O(27)), [Nd(2)(H(2)O)(12)](Mo(8)O(27)) x 6 H(2)O, and [Nd(2)(H(2)O)(6)]Mo(8)O(27) x 3 H(2)O. They adopt one known and three new structure types, which we have determined ab initio from powder X-ray diffraction data. The four compounds contain the same basic structural building block, in the form of RE(2)Mo(8)O(27) (RE = Dy, Nd) chains, which are arranged differently for the two rare earths in the fully hydrated precursor materials. [Dy(2)(H(2)O)(12)](Mo(8)O(27)) x 8 H(2)O comprises isolated Dy(2)Mo(8)O(27) chains assembled in a zigzag manner along the a axis with interspersed crystallized water molecules, which differs from the parallel arrangements of isolated Nd(2)Mo(8)O(27) chains in [Nd(2)(H(2)O)(12)](Mo(8)O(27)) x 6 H(2)O. Partial dehydration of the two precursors leads to new phases [Dy(2)(H(2)O)(6)](Mo(8)O(27)) and [Nd(2)(H(2)O)(6)]Mo(8)O(27) x 3 H(2)O, respectively, prior to complete dehydration, which leads to initially amorphous and eventually crystalline rare-earth molybdenum mixed metal oxides. Both initial transformations occur topotactically. Partial dehydration of the Dy phase condenses the assembly of the Dy(2)Mo(8)O(27) chains principally along the a axis, leading to a 3-dimensional (3D) framework, with each Dy bridging two (Mo(8)O(27))(6-) sheets in the product. The partial dehydration of the Nd precursor condenses the assembly of Nd(2)Mo(8)O(27) chains along the [110] axis, leading to a 3D framework where each Nd bridges three (Mo(8)O(27))(6-) units. Both new dysprosium octamolybdates adopt noncentrosymmetric polar structures in space group P2(1) and are second harmonic generation (SHG) active.

  1. A Sequential Method to Prepare Polymorphs and Solvatomorphs of [Fe(1,3-bpp)2 ](ClO4 )2 ⋅nH2 O (n=0, 1, 2) with Varying Spin-Crossover Behaviour.

    Science.gov (United States)

    Bartual-Murgui, Carlos; Codina, Carlota; Roubeau, Olivier; Aromí, Guillem

    2016-08-26

    Two polymorphs of the spin crossover (SCO) compound [Fe(1,3-bpp)2 ](ClO4 )2 (1 and 2; 1,3-bpp=2-(pyrazol-1-yl)-6-(pyrazol-3-yl)pyridine) were prepared using a novel, stepwise procedure. Crystals of 1 deposit from dry solvents, while 2 is obtained from a solid-state procedure, by sequentially removing lattice H2 O molecules from the solvatomorph [Fe(1,3-bpp)2 ](ClO4 )22 H2 O (22 H2 O), using single-crystal-to-single-crystal (SCSC) transformations. Hydrate 22 H2 O is obtained through the same reaction as 1, now with 2.5 % of water added. Compounds 2 and 22 H2 O are unstable in the atmosphere and absorb or lose one equivalent of water, respectively, to both yield the stable solvatomorph [Fe(1,3-bpp)2 ](ClO4 )2 ⋅H2 O (2⋅H2 O), also following SCSC processes. The four derivatives have been characterised by single-crystal X-ray diffraction (SCXRD). Furthermore, the homogeneity of the various compounds as well as their SCSC interconversions have been confirmed by powder X-ray diffraction (PXRD). Polymorphs 1 and 2 exhibit abrupt SCO behaviour near room temperature with T1/2↑ =279/316 K and T1/2↓ =276/314 K (near 40 K of shift) and different cooperativity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Diaqua-2κ2O-bis(μ-1-oxido-2-naphthoato-1:2κ3O1,O2:O2′;2:3κ3O2:O1,O2′-bis(1-oxido-2-naphthoato-1κ1O2,O2;3κ2O1,O2-hexapyridine-1κ2N,2κ2N,3κ2N-trimanganese(II/III pyridine disolvate dihydrate

    Directory of Open Access Journals (Sweden)

    Daqi Wang

    2008-12-01

    Full Text Available The title complex, [Mn3(C11H6O34(C5H5N6(H2O22H22C5H5N, is a trinuclear mixed oxidation state complex of overline1 symmetry. The three Mn atoms are six-coordinated in the shape of distorted octahedra, each coordinated with an O4N2 set of donor atoms, where the ligands exhibit mono- and bidentate modes. However, the coordination of the MnII ion located on the inversion centre involves water molecules at two coordination sites, whereas that of the two symmetry-related MnIII ions involves an O4N2 set of donor atoms orginating from the organic ligands. Intramolecular C—H...π interactions between neighbouring pyridine ligands stabilize this arrangement. A two-dimensional network parallel to (001 is formed by intermolecular O—H...O hydrogen bonds.

  3. Synthesis and Molecular Structure of 6-Amino-3-benzylmercapto-1,2,4-triazolo[3,4-f][1,2,4]triazin-8(7H-one

    Directory of Open Access Journals (Sweden)

    Gene-Hsiang Lee

    2006-03-01

    Full Text Available The title compound 6-amino-3-benzylmercapto-1,2,4-triazolo[3,4-f][1,2,4]-triazin-8(7H-one (4, molecular formula C11H10N6OS, was obtained by the reaction of3-amino-2-benzyl-6-hydrazino-1,2,4-triazin-5(2H-one (3 with carbon disulfide in awater/pyridine mixture. Compound 4 can also be synthesized by reacting6-amino-3(2Hmercapto-1,2,4-triazolo[3,4-f][1,2,4]triazin-8(7H-one (7 with benzylbromide in methanolic ammonia water. The compound crystallizes in the monoclinicspace group P21/c with a = 7.2926(15, b = 14.456(2, c = 11.436(2 å, β = 105.30(2°, V= 1162.9(4 å3 and Z = 4, resulting in a density Dcalc of 1.567 g/cm3. Molecules of 4 arelinked by extensive intermolecular N-H···N and N-H···O hydrogen bonding [graph set R22 (9]. The structure is further stabilized by π-π stacking interactions. 2

  4. Dipropyl 3,6-diphenyl-1,2-dihydro-1,2,4,5-tetrazine-1,2-dicarboxylate.

    Science.gov (United States)

    Rao, Guo-Wu; Hu, Wei-Xiao

    2003-05-01

    The title compound, C(22)H(24)N(4)O(4), was prepared from propyl chloroformate and 3,6-diphenyl-1,2-dihydro-s-tetrazine. This reaction yields the title compound rather than dipropyl 3,6-diphenyl-1,4-dihydro-s-tetrazine-1,4-dicarboxylate. The 2,3-diazabutadiene group in the central six-membered ring is not planar; the C=N double-bond length is 1.285 (2) A, and the average N-N single-bond length is 1.401 (3) A, indicating a lack of conjugation. The ring has a twist conformation, in which adjacent N atoms lie +/- 0.3268 (17) A from the plane of the ring. The molecule has twofold crystallographic symmetry.

  5. Chemical and structural evolution in the Th-SeO3(2-)/SeO4(2-) system: from simple selenites to cluster-based selenate compounds.

    Science.gov (United States)

    Xiao, Bin; Langer, Eike; Dellen, Jakob; Schlenz, Hartmut; Bosbach, Dirk; Suleimanov, Evgeny V; Alekseev, Evgeny V

    2015-03-16

    While extensive success has been gained in the structural chemistry of the U-Se system, the synthesis and characterization of Th-based Se structures are widely unexplored. Here, four new Th-Se compounds, α-Th(SeO3)2, β-Th(SeO3)2, Th(Se2O5)2, and Th3O2(OH)2(SeO4)3, have been obtained from mild hydrothermal or low-temperature (180-220 °C) flux conditions and were subsequently structurally and spectroscopically characterized. The crystal structures of α-Th(SeO3)2 and β-Th(SeO3)2 are based on ThO8 and SeO3 polyhedra, respectively, featuring a three-dimensional (3D) network with selenite anions filling in the Th channels along the a axis. Th(Se2O5)2 is a 3D framework composed of isolated ThO8 polyhedra interconnected by [Se2O5](2-) dimers. Th3O2(OH)2(SeO4)3 is also a 3D framework constructed by octahedral hexathorium clusters [Th6(μ3-O)4(μ3-OH)4](12+), which are interlinked by selenate groups SeO4(2-). The positions of the vibrational modes associated with both Se(IV)O3(2-) and Se(VI)O4(2-) units, respectively, were determined for four compounds, and the Raman spectra of α- and β-Th(SeO3)2 are compared and discussed in detail.

  6. Photoluminescence properties of blue light excited Ca{sub 8}La{sub 2}(PO{sub 4}){sub 6}O{sub 2}:Eu{sup 3+} red phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yongzheng; Liu, Fengxin; Hou, Jingshan; Zhang, Yan; Zheng, Xinfeng; Zhang, Na [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Zhao, Guoying, E-mail: zhaogy135@sit.edu.cn [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Liao, Meisong [Key Laboratory of Materials for High Powder Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Dai, Guozhang; Long, Mengqiu [School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Liu, Yufeng, E-mail: yfliu@mail.sitp.ac.cn [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China)

    2016-09-15

    A series of red emitting Ca{sub 8}La{sub 2}(PO{sub 4}){sub 6}O{sub 2}:xEu{sup 3+} (0≤x≤0.4) phosphors were synthesized by the conventional solid state reaction, and their photoluminescence properties were investigated in this work. Upon excitation of blue light, the Ca{sub 8}La{sub 2}(PO{sub 4}){sub 6}O{sub 2}:xEu{sup 3+} phosphors exhibit strong red emission at 616 nm, which corresponds to the dominant transition of Eu{sup 3+} ions in Ca{sub 8}La{sub 2}(PO{sub 4}){sub 6}O{sub 2} host, originating from the electric dipole transition {sup 5}D{sub 0}–{sup 7}F{sub 2}. Moreover, Ca{sub 8}La{sub 2}(PO{sub 4}){sub 6}O{sub 2}:0.3Eu{sup 3+} phosphor shows more intense photoluminescence than that of other phosphors, where the concentration of Eu{sup 3+} ion is not equal to 0.3. The CIE chromaticity coordinate (0.657, 0.343) of Ca{sub 8}La{sub 2}(PO{sub 4}){sub 6}O{sub 2}:0.3Eu{sup 3+} phosphor is close to National Television Standard Committee standard value (0.670, 0.330) of red phosphors, which indicates Ca{sub 8}La{sub 2}(PO{sub 4}){sub 6}O{sub 2}:0.3Eu{sup 3+} is potential to apply in white light-emitting diodes as an excellent red emitting phosphor.

  7. Crystal structure and magnetic properties of the Cr-doped spiral antiferromagnet BiMnFe2O6

    International Nuclear Information System (INIS)

    Batuk, Dmitry; De Dobbelaere, Christopher; Tsirlin, Alexander A.; Abakumov, Artem M.; Hardy, An; Van Bael, Marlies K.; Greenblatt, Martha; Hadermann, Joke

    2013-01-01

    Graphical abstract: - Highlights: • The substitution of Cr for Mn in BiMnFe 2 O 6 is possible by the solution–gel method. • The BiCr x Mn 1−x Fe 2 O 6 solid solution is obtained for the x values up to 0.3. • Increasing Cr content lowers the temperature of the antiferromagnetic ordering. - Abstract: We report the Cr 3+ for Mn 3+ substitution in the BiMnFe 2 O 6 structure. The BiCr x Mn 1−x Fe 2 O 6 solid solution is obtained by the solution–gel synthesis technique for the x values up to 0.3. The crystal structure investigation using a combination of X-ray powder diffraction and transmission electron microscopy demonstrates that the compounds retain the parent BiMnFe 2 O 6 structure (for x = 0.3, a = 5.02010(6)Å, b = 7.06594(7)Å, c = 12.6174(1)Å, S.G. Pbcm, R I = 0.036, R P = 0.011) with only a slight decrease in the cell parameters associated with the Cr 3+ for Mn 3+ substitution. Magnetic susceptibility measurements suggest strong similarities in the magnetic behavior of BiCr x Mn 1−x Fe 2 O 6 (x = 0.2; 0.3) and parent BiMnFe 2 O 6 . Only T N slightly decreases upon Cr doping that indicates a very subtle influence of Cr 3+ cations on the magnetic properties at the available substitution rates

  8. Quadruple-layered perovskite (CuCl)Ca2NaNb4O13

    International Nuclear Information System (INIS)

    Kitada, A.; Tsujimoto, Y.; Yamamoto, T.; Kobayashi, Y.; Narumi, Y.; Kindo, K.; Aczel, A.A.; Luke, G.M.; Uemura, Y.J.; Kiuchi, Y.; Ueda, Y.; Yoshimura, K.; Ajiro, Y.; Kageyama, H.

    2012-01-01

    We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca 2 NaNb 4 O 13 . Through a topotactic ion-exchange reaction with CuCl 2 , the precursor RbCa 2 NaNb 4 O 13 presumably having an incoherent octahederal tliting changes into (CuCl)Ca 2 NaNb 4 O 13 with a 2a p ×2a p ×2c p superstructure (tetragonal; a=7.73232(5) Å, c=39.2156(4) Å). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl 4 O 2 octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov′s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0). - Graphical Abstract: We present a quadruple-layered copper oxyhalide (CuCl)Ca 2 NaNb 4 O 13 synthesized through a topotactic ion-exchange reaction of RbCa 2 NaNb 4 O 13 with CuCl 2 . The compound has a well-defined superstructure. Magnetic studies suggest the absence of magnetic order even at 2 K. Highlights: ► (CuCl)Ca 2 NaNb 4 O 13 was prepared by ion-exchange reaction of RbCa 2 NaNb 4 O 13 with CuCl 2 . ► Compound has a 2a p ×2a p ×2c p superstructure (tetragonal; a=7.73 Å, c=39.21 Å). ► Such a well-defined superstructure was not observed in the precursor compound. ► Aleksandrov′s theory and Rietveld study suggest a (++0) octahedral tilting (I4/mmm). ► Magnetic studies revealed the absence of magnetic order down to 2 K.

  9. Design and syntheses of hybrid metal–organic materials based on K{sub 3}[M(C{sub 2}O{sub 4}){sub 3}]·3H{sub 2}O [M(III)=Fe, Al, Cr] metallotectons

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yayong; Zong, Yingxia; Ma, Haoran; Zhang, Ao; Liu, Kang; Wang, Debao, E-mail: dbwang@qust.edu.cn; Wang, Wenqiang; Wang, Lei, E-mail: inorchemwl@126.com

    2016-05-15

    By using K{sub 3}[M(C{sub 2}O{sub 4}){sub 3}]·3H{sub 2}O [M(III)=Fe, Al, Cr] (C{sub 2}O{sub 4}{sup 2−}=oxalate) metallotectons as the starting material, we have synthesized eight novel complexes with formulas [{Fe(C_2O_4)_2(H_2O)_2}{sub 2}]·(H–L{sub 1}){sub 2}·H{sub 2}O 1, [Fe(C{sub 2}O{sub 4})Cl{sub 2}]·(H{sub 2}–L{sub 2}){sub 0.5}·(L{sub 2}){sub 0.5}·H{sub 2}O 2, [{Fe(C_2O_4)_1_._5Cl_2}{sub 2}]·(H–L{sub 3}){sub 4}3, [Fe{sub 2}(C{sub 2}O{sub 4})Cl{sub 8}]·(H{sub 2}–L{sub 4}){sub 22H{sub 2}O 4, K[Al(C{sub 2}O{sub 4}){sub 3}]·(H{sub 2}–L{sub 5})·2H{sub 2}O 5, K[Al(C{sub 2}O{sub 4}){sub 3}]·(H–L{sub 6}){sub 22H{sub 2}O 6, K[Cr(C{sub 2}O{sub 4}){sub 3}]·2H{sub 2}O 7, Na[Fe(C{sub 2}O{sub 4}){sub 3}]·(H–L{sub 6}){sub 22H{sub 2}O 8 (with L{sub 1}=4-dimethylaminopyridine, L{sub 2}=2,3,5,6-tetramethylpyrazine, L{sub 3}=2-aminobenzimidazole, L{sub 4}=1,4-bis-(1H-imidazol-1-yl)benzene, L{sub 5}=1,4-bis((2-methylimidazol-1-yl)methyl)benzene, L{sub 6}=2-methylbenzimidazole). Their structures have been determined by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra and thermogravimetric analyses. Compound 3 is a 2D H-bonded supramolecular architecture. Others are 3D supramolecular structures. Compound 1 shows a [Fe(C{sub 2}O{sub 4}){sub 2}(H{sub 2}O){sub 2}]{sup −} unit and 3D antionic H-bonded framework. Compound 2 features a [Fe(C{sub 2}O{sub 4})Cl{sub 2}]{sup -} anion and 1D iron-oxalate-iron chain. Compound 3 features a [Fe{sub 2}(C{sub 2}O{sub 4}){sub 3}Cl{sub 4}]{sup 4−} unit. Compound 4 features distinct [Fe{sub 2}(C{sub 2}O{sub 4})Cl{sub 8}]{sup 4−} units, which are mutual linked by water molecules to generated a 2D H-bonded network. Compound 5 features infinite ladder-like chains constructed by [Al(C{sub 2}O{sub 4}){sub 3}]{sup 3−} units and K{sup +} cations. The 1D chains are further extended into 3D antionic H-bonded framework through O–H···O H-bonds. Compounds 68 show 2D [KAl(C{sub 2}O

  10. Magnetorresistência colossal em La5/8-yPr yCa3/8MnO3 Magnetoresistance in La5/8-yPr yCa3/8MnO3

    Directory of Open Access Journals (Sweden)

    S. H. Masunaga

    2007-09-01

    Full Text Available Amostras policristalinas de La5/8-yPr yCa3/8MnO3, 0 0,35 também mostram uma transição para o estado de ordenamento de carga/orbital T OC. Uma análise das medidas de ro(T, H sugere a coexistência de pelo menos duas fases distintas nesses materiais: uma ferromagnética-metálica FMM e uma segunda, com ordenamento de carga/orbital e comportamento isolante OCI. Os resultados também permitem concluir que as frações volumétricas dessas fases podem ser manipuladas, alterando-se parâmetros termodinâmicos como T e H. A magnetorresistência MR(T, determinada através das medidas de ro(T, H, foi observada ocorrer em uma larga faixa de temperatura e em todas as amostras pertencentes à série. Amostras ricas em Pr (y > 0,35 revelam um efeito de magnetorresistência colossal amplificado devido à coexistência e competição das FMM e OCI cujas frações volumétricas podem ser alteradas via mudança da temperatura e aplicação de um campo magnético externo.Polycrystalline samples of La5/8-yPr yCa3/8MnO3; 0 0.35 a transition to a charge and orbital-ordered state was also observed. The rho(T, H data analyses suggest the coexistence of at least two ordered phases in these samples: a ferromagnetic metallic phase FMM and a charge and orbital-ordered insulating COI phase.The data also indicate that the volume fraction of these phases can be changed by the variation of thermodynamic parameters like temperature T and magnetic field H. The magnetoresistance MR(T determined from rho(T, H data were observed in a large temperature range for all samples. In addition, samples with y > 0.35 were found to display a pronounced colossal magnetoresistance effect due to a severe competition between FMM and COI coexisting phases.

  11. Growth and Characterization of Organic Marine Dye Compound: 6-Amino-8α-methoxy-5-methyl-4,7-dioxo-1,1a, 2,4,7,8,8a,8b-octahydroazireno[2',3':3,4] pyrrolo[1,2-α]indol- 8-yl]methyl Carbamate

    OpenAIRE

    Jayandran, M.; Balasubramanian, V.

    2011-01-01

    Single crystals of 6-amino-8α-methoxy-5-methyl-4,7-dioxo-1,1a, 2,4,7,8,8a,8b-octahydroazireno[2',3':3,4]pyrrolo[1,2-α]indol-8-yl]methyl carbamate (Mitomycin), an organic marine dye material has been grown from solution by slow evaporation at ambient temperature. The growth of crystals has been carried out at various pH values and the growth was confirmed at pH 6. The chemical composition of the grown crystals was determined by the FTIR spectra. The crystalline nature and its various planes of...

  12. In-plain electric properties of [CaMnO3/REMO3] (RE=Bi, La M=Fe, Fe0.8Mn0.2) superlattices grown by pulsed laser deposition method

    NARCIS (Netherlands)

    Iwata, N.; Watabe, Y.; Oikawa, T.; Takase, K.; Huijben, Mark; Inaba, T.; Oshima, K.; Rijnders, Augustinus J.H.M.; Yamamoto, H.

    2014-01-01

    The [CaMnO3 (CMO)/REMO3] (RE = Bi, La M = Fe, Fe0.8Mn0.2) superlattices show semiconducting behavior with transition temperatures (TEg) of 71, 127, and 151 K in the [CMO/BiFe0.8Mn0.2O3], [CMO/BiFeO3], and [CMO/LaFeO3] superlattices. The formation of a magnetic polaron is expected in the CMO layer of

  13. General synthesis and structural evolution of a layered family of Ln8(OH)20Cl4 x nH2O (Ln = Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Y).

    Science.gov (United States)

    Geng, Fengxia; Matsushita, Yoshitaka; Ma, Renzhi; Xin, Hao; Tanaka, Masahiko; Izumi, Fujio; Iyi, Nobuo; Sasaki, Takayoshi

    2008-12-03

    The synthesis process and crystal structure evolution for a family of stoichiometric layered rare-earth hydroxides with general formula Ln(8)(OH)(20)Cl(4) x nH(2)O (Ln = Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Y; n approximately 6-7) are described. Synthesis was accomplished through homogeneous precipitation of LnCl(3) x xH(2)O with hexamethylenetetramine to yield a single-phase product for Sm-Er and Y. Some minor coexisting phases were observed for Nd(3+) and Tm(3+), indicating a size limit for this layered series. Light lanthanides (Nd, Sm, Eu) crystallized into rectangular platelets, whereas platelets of heavy lanthanides from Gd tended to be of quasi-hexagonal morphology. Rietveld profile analysis revealed that all phases were isostructural in an orthorhombic layered structure featuring a positively charged layer, [Ln(8)(OH)(20)(H(2)O)(n)](4+), and interlayer charge-balancing Cl(-) ions. In-plane lattice parameters a and b decreased nearly linearly with a decrease in the rare-earth cation size. The interlamellar distance, c, was almost constant (approximately 8.70 A) for rare-earth elements Nd(3+), Sm(3+), and Eu(3+), but it suddenly decreased to approximately 8.45 A for Tb(3+), Dy(3+), Ho(3+), and Er(3+), which can be ascribed to two different degrees of hydration. Nd(3+) typically adopted a phase with high hydration, whereas a low-hydration phase was preferred for Tb(3+), Dy(3+), Ho(3+), Er(3+), and Tm(3+). Sm(3+), Eu(3+), and Gd(3+) samples were sensitive to humidity conditions because high- and low-hydration phases were interconvertible at a critical humidity of 10%, 20%, and 50%, respectively, as supported by both X-ray diffraction and gravimetry as a function of the relative humidity. In the phase conversion process, interlayer expansion or contraction of approximately 0.2 A also occurred as a possible consequence of absorption/desorption of H(2)O molecules. The hydration difference was also evidenced by refinement results. The number of coordinated water

  14. Synthesis and characterization of the new copper indium phosphate Cu_8In_8P_4O_3_0

    International Nuclear Information System (INIS)

    Hanzelmann, Christian; Weimann, Iren; Feller, Joerg; Zak, Zdirad

    2014-01-01

    The system CuO/In_2O_3/P_2O_5 has been investigated using solid state reaction between CuO, In_2O_3 and (NH_4)_2HPO_4 in silica glass crucibles at 900 C. The powder samples were characterized by X-ray diffraction, thermal analysis and FT-IR spectroscopy. Orange single crystals of the new quaternary phase were achieved by the process of crystallization with mineralizers in sealed silica glass ampoules. They were then analyzed with EDX and single-crystal X-ray analysis in which the composition Cu_8In_8P_4O_3_0 with the triclinic space group P anti 1 (No 2) with a = 7,2429(14) Aa, b = 8,8002(18) Aa, c = 10,069(2) Aa, α = 103,62(3) , β = 106,31(3) , γ = 101,55(3) and Z = 1 was found. The three-dimensional framework consists of [InO_6] octahedra and distorted [CuO_6] octahedra, overcaped [InO_7] prisms and [PO_4] tetrahedra, also trigonal [(CuIn)O_5] bipyramids and distorted [(CuIn)O_6] octahedra, where copper and indium are partly exchanged against each other. Cu_8In_8P_4O_3_0 exhibits an incongruent melting point at 1023 C. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. X-ray photoelectron investigation of UO2(ClO4)2 interaction with diabase

    International Nuclear Information System (INIS)

    Teterin, Yu.A.; Nefedov, V.I.; Ivanov, K.E.; Baev, A.S.; Gajpel', G.; Rajkh, T.; Niche, Kh.

    1996-01-01

    X-ray diffraction study was made on interaction of soluble uranyl perchlorate with diabase, composing rocks in regions of Chelyabinsk and Chernobyl accidents and in places of radioactive waste burials. Absence of ClO 4 - anion in analyzed products of UO 2 (ClO 4 ) 2 interaction with diabase testifies to the absence of physio- or chemosorbed UO 2 (ClO 4 ) 2 layer on its surface. Formation of uranyl compounds (uranyl hydroxides) on diabase surface was confirmed, and bond lengths for these compounds were determined. Reaction of substitution of uranium ions for calcium ions proceeds more actively in the surface layers of diabase grains. 4 refs.; 3 tabs

  16. Low-temperature, high yield synthesis, and convenient isolation of the high-electron-density cluster compound Ta6Br14.8H2O for use in biomacromolecular crystallographic phase determination.

    Science.gov (United States)

    Hay, Daniel N T; Messerle, Louis

    2002-09-01

    Reduction of TaBr(5) with Ga in the presence of KBr in a sealed borosilicate ampule at 400 degrees, followed by aqueous Soxhlet extraction and addition of stannous bromide and hydrobromic acid to the extract, yielded Ta(6)Br(14).8H(2)O in 80-84% yield. The new procedure provides a convenient, low temperature, high yield route to the synthesis of the title compound from inexpensive precursors.

  17. Identification and analytical characterization of nine synthetic cathinone derivatives N-ethylhexedrone, 4-Cl-pentedrone, 4-Cl-α-EAPP, propylone, N-ethylnorpentylone, 6-MeO-bk-MDMA, α-PiHP, 4-Cl-α-PHP, and 4-F-α-PHP.

    Science.gov (United States)

    Liu, Cuimei; Jia, Wei; Li, Tao; Hua, Zhendong; Qian, Zhenhua

    2017-08-01

    Clinical and forensic toxicology laboratories are continuously confronted by analytical challenges when dealing with the new psychoactive substances (NPS) phenomenon. In this study, the analytical characterization of nine synthetic cathinones is described: 2-(ethylamino)-1-phenylhexan-1-one (N-ethylhexedrone 1), 1-(4-chlorophenyl)-2-(methylamino)pentan-1-one (4-Cl-pentedrone 2), 1-(4-chlorophenyl)-2-(ethylamino)pentan-1-one (4-Cl-α-EAPP 3), 1-(3,4-methylenedioxyphenyl)-2-propylaminopropan-1-one (propylone 4), 1-(3,4-methylenedioxyphenyl)-2-ethylaminopentan-1-one (N-ethylnorpentylone 5), 1-(6-methoxy-3,4-methylenedioxyphenyl)-2-methylaminopropan-1-one (6-MeO-bk-MDMA 6), 4-methyl-1-phenyl-2-(pyrrolidin-1-yl)pentan-1-one (α-PiHP 7), 1-(4-chlorophenyl)-2-(pyrrolidin-1-yl)hexan-1-one (4-Cl-α-PHP 8), and 1-(4-fluorophenyl)-2-(pyrrolidin-1-yl)hexan-1-one (4-F-α-PHP 9). The identification was based on ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UHPLC-QTOF-MS), gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance (NMR) spectroscopy. The mass-spectral fragmentations of these compounds following collision-induced dissociation (CID) and electron ionization (EI) were studied to assist forensic laboratories in identifying these compounds or other substances with similar structure in their case work. To our knowledge, no analytical data about the compounds 1-4, 7, and 8 have appeared until now, making this the first report on these compounds. The GC-MS data of 5, 6 and 9 has been reported, but this study added the LC-MS, Fourier Transform Infrared (FTIR) and NMR data for additional characterization. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Preparation and electrochemical properties of lamellar MnO{sub 2} for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jun; Wei, Tong [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Cheng, Jie [Research Institute of Chemical Defense, Beijing 100083 (China); Fan, Zhuangjun, E-mail: fanzhj666@163.com [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Zhang, Milin [Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)

    2010-02-15

    Lamellar birnessite-type MnO{sub 2} materials were prepared by changing the pH of the initial reaction system via hydrothermal synthesis. The interlayer spacing of MnO{sub 2} with a layered structure increased gradually when the initial pH value varied from 12.43 to 2.81, while the MnO{sub 2}, composed of {alpha}-MnO{sub 2} and {gamma}-MnO{sub 2}, had a rod-like structure at pH 0.63. Electrochemical studies indicated that the specific capacitance of birnessite-type MnO{sub 2} was much higher than that of rod-like MnO{sub 2} at high discharge current densities due to the lamellar structure with fast intercalation/deintercalation of protons and high utilization of MnO{sub 2}. The initial specific capacitance of MnO{sub 2} prepared at pH 2.81 was 242.1 F g{sup -1} at 2 mA cm{sup -2} in 2 mol L{sup -1} (NH{sub 4}){sub 2}SO{sub 4} aqueous electrolyte. The capacitance increased by about 8.1% of initial capacitance after 200 cycles at a current density of 100 mA cm{sup -2}.

  19. A three-dimensional coordination polymer based on 1,2,3-triazole-4,5-dicarboxylic acid (H{sub 3}tda): ([Cd{sub 12}(tda){sub 8}(H{sub 2}O){sub 11}] · (H{sub 2}O)6.25){sub n}

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xin-Hui, E-mail: iamxhzhou@njupt.edu.cn; Chen, Qiang [Nanjing University of Posts and Telecommunications, Key Laboratory for Organic Electronics and Information Displays and Institute of Advanced Materials, National Jiangsu Syngerstic Innovation Center for Advanced Materials (SICAM) (China)

    2017-03-15

    The title coordination polymer ([Cd{sub 12}(tda){sub 8}(H{sub 2}O){sub 11}] · (H{sub 2}O){sub 6.25}){sub n} (H{sub 3}tda = 1,2,3-triazole-4,5-dicarboxylic acid), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex crystallizes in orthorhombic sp. gr. Pmn2{sub 1} with Z = 4. The Cd{sub 2} unit doublebridged by one carboxylate oxygen atom and two neighboring nitrogen atoms from the tda{sup 3–} ligands are linked by the tda{sup 3–}ligands to lead to the 2D (4,4) network in the ac plane. The almost coplanar Cd{sub 2}(μ{sub 5}-tda){sub 2} unit comprised of two Cd ions double-bridged by two tda{sup 3–} ligands through the neighboring nitrogen atoms is connected with the other four Cd{sub 2}(μ{sub 5}-tda){sub 2} units form the undulating 2D network in the ac plane. The (4,4) networks and undulating 2D networks are alternatively connected along the b axis by the tda{sup 3–} ligands coordinating to the Cd ions to form the 3D framework.

  20. An unexpected oxidation: NaK5Cl2(S2O62 revisited

    Directory of Open Access Journals (Sweden)

    William T. A. Harrison

    2017-02-01

    Full Text Available The title compound, NaK5Cl2(S2O62 [systematic name: sodium pentapotassium dichloride bis(dithionate], arose as an unexpected product from an organic synthesis that used dithionite (S2O42− ions as a reducing agent to destroy excess permanganate ions. Compared to the previous study [Stanley (1953. Acta Cryst. 6, 187–196], the present tetragonal structure exhibits a root 2a × root 2a × c super-cell due to subtle changes in the orientations of the dithionate anions. The structure can be visualized as a three-dimensional framework of [001] columns of alternating trans-NaO4Cl2 and KO4Cl2 octahedra cross-linked by the dithionate ions with the interstices occupied by KO6Cl2 polyhedra to generate a densely packed three-dimensional framework. The asymmetric unit comprises two sodium ions (site symmetries 4 and -4, four potassium ions (site symmetries = -4, 4, 1 and 1, three chloride ions (site symmetries = 4, 4 and 2 and two half-dithionate ions (all atoms on general positions. Both dithionate ions are completed by crystallographic inversion symmetry. The crystal chosen for data collection was found to be rotationally twinned by 180° about the [100] axis in reciprocal space with a 0.6298 (13:0.3702 (13 domain ratio.

  1. 9-Furfurylidene-2,3-dimethyl-6,7,8,9-tetrahydro-4H-thieno[2′,3′:4,5]pyrimidino[1,2-a]pyridin-4-one

    Directory of Open Access Journals (Sweden)

    Khusnutdin M. Shakhidoyatov

    2010-03-01

    Full Text Available The title compound, C17H16N2O2S, was obtained by condensation of 2,3-dimethylthieno[2′,3′:4,5]pyrimidino[1,2-a]pyridin-4-one with furfural in the presence of sodium hydroxide. One of the methylene groups of the tetrahydropyrido ring is disordered over two positions in a 0.87 (1:0.13 (1 ratio. The thieno[2,3-d]pyrimidin-4-one unit and the furan ring are both planar (r.m.s. deviation = 0.535 Å, and coplanar with each other, forming a dihedral angle of 5.4 (1°. Four weak intermolecular hydrogen bonds (C—H...O and C—H...N are observed in the structure, which join molecules into a network parallel to (101.

  2. Pembuatan La0,8Ca0,2MnO3 sebagai Katoda pada Solid Oxide Fuel Cell (SOFC dan Karakteristiknya

    Directory of Open Access Journals (Sweden)

    Riska Ekawati

    2007-06-01

    Full Text Available The making of La0,8Ca0,2MnO3 cathode material of solid oxide fuel cell from lanthanum oxide (La2O3, calcium oxide (CaO, and manganese carbonate hydrate (MnCO3.H2O has been done using tape casting method. Time of firing the La0,8Ca0,2MnO3 varied. The values of t = 30 minutes, 60 minutes and 120 minutes. Microstructure of these materials was analyzed and characterized by means of their electric conductivity, XRD (x ray diffraction and SEM (scanning electron microscope. It is found that formulated micro structure is orthorhombic. The result of measurement shows that density is in linear (positive correlation with increasing of holding time of firing, porosity and coefficient of thermal expansion is negatively correlated with density and electric conductivity is in linear (positive correlation with increase density.

  3. Sodium storage capability of spinel Li4Mn5O12

    International Nuclear Information System (INIS)

    Zhang, Jiaolong; Wang, Wenhui; Li, Yingshun; Yu, Denis Y.W.

    2015-01-01

    Highlights: • Electrochemical behavior of spinel Li 4 Mn 5 O 12 is examined in Na-ion battery. • A capacity of 120.7 mAh g −1 is obtained during the first sodiation process. • Na storage performance is found to be strongly dependent on particle size. • Ion-exchange between Li ions and Na ions occurs in Li 4 Mn 5 O 12 structure upon cycling. • Loss of crystallinity with cycling, leading to capacity fading. - Abstract: Spinel Li 4 Mn 5 O 12 , a well-known 3 V Li-ion battery (LIB) material with excellent cycling stability and good rate capability, is examined as Na-ion battery (NIB) cathode for the first time. Electrochemical studies clearly show that Na ions can be reversibly inserted into and extracted from the three-dimensional spinel structure. However, unlike in LIB, the available capacity in NIB is strongly dependent on the particle size and current rate due to the sluggish Na-ion transport in solid phase. Cycle performance of Li 4 Mn 5 O 12 in NIB is also inferior to that in LIB. Ex-situ X-ray diffraction study indicates a gradual loss of crystallinity with cycling, and that the crystal lattice undergoes an irreversible expansion during the initial 20 cycles. Inductively coupled plasma spectroscopy shows a decrease of Li/Mn ratio in Li 4 Mn 5 O 12 with cycling. The results suggest that Li ions are removed from the material during the charging process. The charge-discharge mechanism is also discussed in the paper.

  4. Structural characterization of Li1.2v3o8 insertion electrodes by single-crystal x-ray-diffraction

    CSIR Research Space (South Africa)

    De Picciotto, LA

    1993-08-01

    Full Text Available The crystal structures of Li1.2V3O8 and a lithiated product Li4.0V3O8 have been determined by single-crystal X-ray diffraction methods. The structure refinement of Li1.2V308 confirms that of Li1+xV3O8(x almost-equal-to 0) reported by Wadsley thirty...

  5. Crystal structures of NiSO4·9H2O and NiSO4·8H2O: magnetic properties, stability with respect to morenosite (NiSO4·7H2O), the solid-solution series (Mg x Ni1-x )SO4·9H2O

    Science.gov (United States)

    Fortes, A. D.; Knight, K. S.; Gibbs, A. S.; Wood, I. G.

    2018-02-01

    Since being discovered initially in mixed-cation systems, a method of forming end-member NiSO4·9H2O and NiSO4·8H2O has been found. We have obtained powder diffraction data from protonated analogues (with X-rays) and deuterated analogues (using neutrons) of these compounds over a range of temperatures, allowing us to determine their crystal structures—including all H-atoms—and to characterise the transitions on warming from 220 to 278 K; glass → 9-hydrate → 8-hydrate + ice → 7-hydrate + ice → partial melt (7-hydrate + liquid). NiSO4·8D2O is triclinic, space-group P\\bar {1} , Z = 2, with unit cell parameters at 150 K, a = 6.12463(8) Å, b = 6.8401(1) Å, c = 12.5339(2) Å, α = 92.846(1)°, β = 97.822(1)°, γ = 96.627(1)° and V = 515.58(1) Å3. The structure consists of two symmetry-inequivalent Ni(D2O)6 octahedra on sites of \\bar {1} symmetry. These are directly joined by a water-water H-bond to form chains of octahedra parallel with the c-axis at x = 0. Two interstitial water molecules serve both to bridge the Ni(D2O)6 octahedral chains in the b-c plane and also to connect with the SO4 2- tetrahedral oxyanion. These tetrahedra are linked by the two interstitial water molecules in a reticular motif to form sheets perpendicular to c. NiSO4·9D2O is monoclinic, space-group P21/c, Z = 4, with unit-cell parameters at 150 K, a = 6.69739(6) Å, b = 11.8628(1) Å, c = 14.5667(1) Å, β = 94.9739(8)° and V = 1152.96(1) Å3. The structure is isotypic with the Mg analogue described elsewhere (Fortes et al., Acta Cryst B 73:47‒64, 2017b). It shares the motif of H-bonded octahedral chains with NiSO4·8D2O, although in the enneahydrate these run parallel with the b-axis at x = 0. Three interstitial water molecules bridge the Ni(D2O)6 octahedra to the SO4 2- tetrahedral oxyanion. The tetrahedra sit at x ≈ 0.5 and are linked by two of the three interstitial water molecules in a pentagonal motif to form ribbons parallel with b. A solid-solution series

  6. The crystal structures of 3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-6-O-triphenylmethyl-α-d-glucofuranose and its azide displacement product

    Directory of Open Access Journals (Sweden)

    Zane Clarke

    2018-06-01

    Full Text Available The effect of different leaving groups on the substitution versus elimination outcomes with C-5 d-glucose derivatives was investigated. The stereochemical configurations of 3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-6-O-triphenylmethyl-α-d-glucofuranose, C36H38O8S (3 [systematic name: 1-[(3aR,5R,6S,6aR-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl-2-(trityloxyethyl methanesulfonate], a stable intermediate, and 5-azido-3-O-benzyl-5-deoxy-1,2-O-isopropylidene-6-O-triphenylmethyl-β-l-idofuranose, C35H35N3O5 (4 [systematic name: (3aR,5S,6S,6aR-5-[1-azido-2-(trityloxyethyl]-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole], a substitution product, were examined and the inversion of configuration for the azido group on C-5 in 4 was confirmed. The absolute structures of the molecules in the crystals of both compounds were confirmed by resonant scattering. In the crystal of 3, neighbouring molecules are linked by C—H...O hydrogen bonds, forming chains along the b-axis direction. The chains are linked by C—H...π interactions, forming layers parallel to the ab plane. In the crystal of 4, molecules are also linked by C—H...O hydrogen bonds, forming this time helices along the a-axis direction. The helices are linked by a number of C—H...π interactions, forming a supramolecular framework.

  7. Ilyukhinite (H3O,Na)14Ca6Mn2Zr3Si26O72(OH)2 • 3H2O, a New Mineral of the Eudialyte Group

    Science.gov (United States)

    Chukanov, N. V.; Rastsvetaeva, R. K.; Rozenberg, K. A.; Aksenov, S. M.; Pekov, I. V.; Belakovsky, D. I.; Kristiansen, R.; Van, K. V.

    2017-12-01

    A new eudialyte-group mineral, ilyukhinite, ideally (H3O,Na)14Ca6Mn2Zr3Si26O72(OH)2 · 3H2O, has been found in peralkaline pegmatite at Mt. Kukisvumchorr, Khibiny alkaline pluton, Kola Peninsula, Russia. It occurs as brownish orange, with vitreous luster anhedral grains up to 1 mm across in hydrothermally altered peralkaline rock, in association with aegirine, murmanite, albite, microcline, rhabdophane-(Ce), fluorite, sphalerite and molybdenite. The Mohs hardness is 5; cleavage is not observed. D meas 2.67(2), D calc 2.703 g/cm3. Ilyukhinite is optically uniaxial (-): ω = 1.585(2), ɛ = 1.584(2). The IR spectrum is given. The average chemical composition of ilyukhinite (wt %; electron microprobe, ranges given in parentheses; H2O determined by gas chromatography) is as follows: 3.07 (3.63-4.43) Na2O, 0.32 (0.28-0.52) K2O, 10.63 (10.26-10.90) CaO, 3.06 (2.74-3.22) MnO, 1.15 (0.93-1.37) FeO, 0.79 (0.51-0.89) La2O3, 1.21 (0.97-1.44) Ce2O3, 0.41 (0.30-0.56) Nd2O3, 0.90 (0.77-1.12) TiO2, 10.94 (10.15-11.21) ZrO2, 1.40 (0.76-1.68) Nb2O5, 51.24 (49.98-52.28) SiO2, 1.14 (0.89-1.37) SO3, 0.27 (0.19—0.38) Cl, 10.9(5 )H2O,-0.06-O = C1, total is 98.27. The empirical formula is H36.04(Na3.82K0.20)(Ca5.65Ce0.22La0.14Nd0.07)(Mn1.285Fe0.48)(Zr2.645Ti0.34)Nb0.31Si25.41S0.42Cl0.23O86.82. The crystal structure has been solved ( R = 0.046). Ilyukhinite is trigonal, R3 m; a = 14.1695(6) Å, b = 31.026(1) Å, V = 5394.7(7) Å3, Z = 3. The strongest XRD reflections [ d, Å (I, %) ( hkl)] are 11.44 (82) (101), 7.09 (70) (110), 6.02 (44) (021), 4.371 (89) 205), 3.805 (47) (303, 033), 3.376 (41) (131), 2.985 (100) (315, 128), 2.852 (92) (404). Ilyukhinite was named in memory of Vladimir V. Ilyukhin (1934-1982), an outstanding Soviet crystallographer. The type specimen of ilyukhinite has been deposited in the collection of the Natural History Museum, University of Oslo, Norway.

  8. Fast synthesis of the polycrystalline materials on the base of Zn 3 V2 MoO11 and Zn 2.5 VMoO8

    Directory of Open Access Journals (Sweden)

    Maya Markova-Velichkova

    2009-12-01

    Full Text Available In our study we applied two different techniques for the preparation of Zn3V2MoO11 and Zn2.5VMoO8 polycrystalline materials - melt quenching method (up-bottom and mechanochemical synthesis (bottom- up. These compounds belong to the family of materials with general formula M2.5VMoO8 (M=Zn, Mg, Mn, Co. They are potential candidates as catalysts in processes of selective oxidation of hydrocarbons. Until now, these two compounds were obtained by conventional solid state reaction. Using infrared spectroscopy and X-ray diffraction we proved that the melt quenching technique is a quite appropriate method for the synthesis of bulk Zn3V2-MoO11 phase. Mechanochemical activation is more appropriated for the preparation of nonosized Zn2.5VMoO8 powder. It was established that the melt quenching technique and mechanochemical activation are faster in comparison with conventional ceramic methods for the given synthesis.

  9. Use of MnO2 and MnO2 SiO2 for sorbing of Sr-90 from liquid rad waste

    International Nuclear Information System (INIS)

    Subiarto; Las, Thamzil; Aan BH, Martin; Utomo, Cahyo Hari

    1998-01-01

    The synthesis of MnO 2 adsorbent and MnO 2 -SiO 2 composite has been done. MnO 2 synthesis is done by the reaction of KMnO 4 , Mn(NO 3 ) 2 .4H 2 O and Na 2 S 2 O 4 ( MnO 2 -A, MnO 2 -B, and MnO 2 -T ). MnO 2 . SiO 2 is made from KMnO 4 , Na 2 SiO 3 , and H 2 O 2 . The result obtained show the best Sr-90 sorption by MnO 2 -A with Kd = 2085.63 ml/g, by MnO 2 -L with Kd = 755.09 ml/g, and by MnO 2 - SiO 2 composite with Kd = 1466.51 ml/g. From this result, we can conclude that MnO 2 -SiO 2 can be expanded for Sr-90 sorption from liquid radioactive waste. (author)

  10. Chemistry of the oxophosphinidene ligand. 2. Reactivity of the anionic complexes [MCp{P(O)R*}(CO)(2)](-) (M = Mo, W; R* = 2,4,6-C(6)H(2)(t)Bu(3)) toward electrophiles based on elements different from carbon.

    Science.gov (United States)

    Alonso, María; Alvarez, M Angeles; García, M Esther; Ruiz, Miguel A; Hamidov, Hayrullo; Jeffery, John C

    2010-12-20

    The anionic oxophosphinidene complexes (H-DBU)[MCp{P(O)R*}(CO)(2)] (M = Mo, W; R* = 2,4,6-C(6)H(2)(t)Bu(3); Cp = η(5)-C(5)H(5), DBU = 1,8-diazabicyclo [5.4.0] undec-7-ene) displayed multisite reactivity when faced with different electrophilic reagents. The reactions with the group 14 organochloride compounds ER(4-x)Cl(x) (E = Si, Ge, Sn, Pb) led to either phosphide-like, oxophosphinidene-bridged derivatives [MCp{P(OE')R*}(CO)(2)] (E' = SiMe(3), SiPh(3), GePh(3), GeMe(2)Cl) or to terminal oxophosphinidene complexes [MCp{P(O)R*}(CO)(2)(E')] (E' = SnPh(3), SnPh(2)Cl, PbPh(3); Mo-Pb = 2.8845(4) Å for the MoPb compound). A particular situation was found in the reaction with SnMe(3)Cl, this giving a product existing in both tautomeric forms, with the phosphide-like complex [MCp{P(OSnMe(3))R*}(CO)(2)] prevailing at room temperature and the tautomer [MCp{P(O)R*}(CO)(2)(SnMe(3))] being the unique species present below 203 K in dichloromethane solution. The title anions also showed a multisite behavior when reacting with transition-metal based electrophiles. Thus, the reactions with the complexes [M'Cp(2)Cl(2)] (M' = Ti, Zr) gave phosphide-like derivatives [MCp{P(OM')R*}(CO)(2)] (M = Mo, M' = TiCp(2)Cl, ZrCp(2)Cl; M = W, M' = ZrCp(2)Cl), displaying a bridging κ(1),κ(1)-P,O- oxophosphinidene ligand connecting MCp(CO)(2) and M'Cp(2)Cl metal fragments (W-P = 2.233(1) Å, O-Zr = 2.016(4) Å for the WZr compound]. In contrast, the reactions with the complex [AuCl{P(p-tol)(3)}] gave the metal-metal bonded derivatives trans-[MCp{P(O)R*}(CO)(2){AuP(p-tol)(3)}] (M = Mo, W; Mo-Au = 2.7071(7) Å). From all the above results it was concluded that the terminal oxophosphinidene complexes are preferentially formed under conditions of orbital control, while charge-controlled reactions tend to give derivatives with the electrophilic fragment bound to the oxygen atom of the oxophosphinidene ligand (phosphide-like, oxophosphinidene-bridged derivatives).

  11. Mild hydrothermal synthesis, crystal structure, thermal behavior, spectroscopic and magnetic properties of the (NH4)[Fe(AsO4)1-x(PO4)xF] (x=0.3, 0.6, 0.8) series. Thermal transformation of (NH4)[Fe(AsO4)0.7(PO4)0.3F] into the textural porous orthorhombic Fe(AsO4)0.7(PO4)0.3

    International Nuclear Information System (INIS)

    Berrocal, Teresa; Mesa, Jose L.; Pizarro, Jose L.; Bazan, Begona; Lezama, Luis; Arriortua, Maria I.; Rojo, Teofilo

    2009-01-01

    The (NH 4 )[Fe(AsO 4 ) 1-x (PO 4 ) x F] (x=0.3, 0.6, 0.8) series of compounds has been synthesized under mild hydrothermal conditions. The compounds crystallize in the orthorhombic Pna2 1 space group, with the unit-cell parameters a=13.1718(1), b=6.5966(6), c=10.797(1) A for x=0.3; a=13.081(1), b=6.5341(6), c=10.713(1) A for x=0.6 and a=13.0329(9), b=6.4994(4), c=10.6702(6) A for x=0.8, with the volumes 938.6(1), 915.7(1) and 903.8(1) A 3 , respectively, with Z=8. Single crystals of (NH 4 )[Fe(AsO 4 ) 0.7 (PO 4 ) 0.3 F] heated under air atmosphere at 465 deg. C remain as single crystals, changing the composition to Fe(AsO 4 ) 0.7 (PO 4 ) 0.3 . This later phase belongs to the orthorhombic Imam space group, with the unit cell parameters a=13.328(2), b=6.5114(5), c=10.703(1) A, V=928.9(2) A 3 and Z=12. The crystal structure of the ammonium phases consists of a KTP three-dimensional framework constructed by chains formed by alternating Fe(2)O 4 F 2 or Fe(1)O 4 F 2 octahedra and As/P(2)O 4 or As/P(1)O 4 tetrahedra, respectively. These octahedra and tetrahedra are linked by a common oxygen vertex. The chains run along the 'a' and 'b' crystallographic axes. The crystal structure of Fe(AsO 4 ) 0.7 (PO 4 ) 0.3 is a three-dimensional skeleton derived from that of the precursor, formed from (100) sheets stacked along the [001] direction, and interconnected by chains of alternating Fe(2)O 6 octahedra and As/P(2)O 4 tetrahedra sharing a vertex in the 'a' direction. Transmission electronic microscopy of this compound indicates the existence of unconnected external cavities with a BET surface area of 3.91(3) m 2 g -1 . The diffuse reflectance spectra in the visible region show the forbidden electronic transitions characteristic of the Fe(III) d 5 -high spin cation in slightly distorted octahedral geometry, for all the compounds. The ESR spectra for all the compounds, carried out from room temperature to 4.2 K, remain isotropic with variation in temperature; the g-value is 1

  12. Near-UV and blue wavelength excitable Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} high efficiency red phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Khanna, A. [Smart Lighting Engineering Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Electrical Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Dutta, P.S., E-mail: duttap@rpi.edu [Smart Lighting Engineering Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States); Electrical Computer and Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180 (United States)

    2015-05-15

    Red phosphors with narrow emission around 615 nm (with FWHM~5–10 nm) having chemical compositions of A{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} (A=Mg, Sr) have been found to exhibit the highest luminescence amongst the molybdate–tungstate family when excited by sources in the 380–420 nm wavelength range. Thus they are most suitable for enhancing color rendering index and lowering color temperature in phosphor converted white LEDs (pc-WLEDs) with near-UV/blue LED excitation sources. The excitation band edge in the near UV/blue wavelength in the reported phosphor has been attributed to the coordination environment of the transition metal ion (Mo{sup 6+}, W{sup 6+}) and host crystal structure. Furthermore the quantum efficiency of the phosphors has been enhanced by adjusting activator concentration, suitable compositional alloying using substitutional alkaline earth metal cations and charge compensation mechanisms. - Graphical abstract: The charge transfer excitation of orthorhombic Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} is significantly higher than tetragonal CaMoO{sub 4}: Eu{sup 3+} phosphors making Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} prime candidates for fabrication of warm white phosphor-converted LEDs. - Highlights: • LED excitable Mg{sub 0.6}Ca{sub 2.16}Mo{sub 0.2}W{sub 0.8}O{sub 6}: Eu{sub 0.12}{sup 3+}/Na{sub 0.12}{sup +} phosphors were synthesized. • These phosphors are 10 times more intense than CaMoO{sub 4}: Eu{sup 3+} red phosphors. • Their intensity and efficiency were enhanced by materials optimization techniques. • Such techniques include compositional alloying, charge compensation, etc.

  13. Crystal structure of methyl 2-(2H-1,3-benzodioxol-5-yl-7,9-dibromo-8-oxo-1-oxaspiro[4.5]deca-2,6,9-triene-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Lucimara Julio Martins

    2014-12-01

    Full Text Available The title compound, C18H12Br2O6, was synthesized from Morita–Baylis–Hillman adducts. It incorporates the brominated spiro-hexadienone moiety typically exhibited by compounds of this class that exhibit biological activity. Both the brominated cyclohexadienone and the central five-membered rings are nearly planar (r.m.s. deviations of 0.044 and 0.016 Å, respectively, being almost perpendicularly oriented [interplanar angle = 89.47 (5°]. With respect to the central five-membered ring, the brominated cyclohexadienone ring, the benzodioxol ring and the carboxylate fragment make C—O—C—C, O—C—C—C and C—C—C—O dihedral angles of −122.11 (8, −27.20 (11 and −8.40 (12°, respectively. An intramolecular C—H...O hydrogen bond occurs. In the crystal, molecules are linked by non-classical C—H...O and C—H...Br hydrogen bonds resulting in a molecular packing in which the brominated rings are in a head-to-head orientation, forming well marked planes parallel to the b axis.

  14. A new, high energy rechargeable lithium ion battery with a surface-treated Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode and a nano-structured Li{sub 4}Ti{sub 5}O{sub 12} anode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaoyu; Huang, Tao; Yu, Aishui, E-mail: asyu@fudan.edu.cn

    2015-11-05

    Through elaborate design, a new rechargeable lithium ion battery has been developed by comprising a surface-treated Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode and a nano-structured Li{sub 4}Ti{sub 5}O{sub 12} anode. After precondition Na{sub 2}S{sub 2}O{sub 8} treatment, the initial coulombic efficiency of Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode has been significantly increased and can be compatible with that of the nano-structured Li{sub 4}Ti{sub 5}O{sub 12} anode. The optimization of structure and morphology for both active electrode materials result in their remarkable electrochemical performances in respective lithium half-cells. Ultimately, the rechargeable lithium ion full battery consisting of both electrodes delivers a specific capacity of 99.0 mAh g{sup −1} and a practical energy density of 201 Wh kg{sup −1}, based on the total weight of both active electrode materials. Furthermore, as a promising candidate in the lithium ion battery field, this full battery also achieves highly attractive electrochemical performance with high coulombic efficiency, excellent cycling stability and outstanding rate capability. Thus the proposed battery displays broad practical application prospects for next generation of high-energy lithium ion battery. - Highlights: • The Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode is surface-treated by Na{sub 2}S{sub 2}O{sub 8}. • The nano-sized Li{sub 4}Ti{sub 5}O{sub 12} anode is obtained by a solid-state method. • A new Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2}/Li{sub 4}Ti{sub 5}O{sub 12} lithium ion battery is developed. • The battery shows high coulombic efficiency, specific capacity and energy density. • The battery shows high capacity retention rate and good high-rate capability.

  15. Mass spectrometric determination of stability of gaseous BaMoO2, Ba2MoO4, Ba2MoO5, Ba2Mo2O8 molecules

    International Nuclear Information System (INIS)

    Kudin, L.S.; Balduchchi, Dzh.; Dzhil'i, G.; Gvido, M.

    1982-01-01

    During the mass spectrometric investigation of BaCrO 4 evaporation Cr + , Ba + , BaO + main ions are recorded as well as BaMoO 4 + , BaMoO 3 + , BaMoO 2 + , BaMoO + , BaMoO 4 + , Ba 2 MoO 5 + , BaMo 2 O 8 + ions - the products of ionization of three-component (Ba, Mo, M) molecules, forming as a result of substance chemical interaction with the material of an effusion cell (Mo). Heats of formation of BaMoO 2 , Ba 2 MoO 4 , Ba 2 MoO 5 and Ba 2 Mo 2 O 8 molecules which constituted - 577+-70, -1343+-115, -1464+-70, -2393+-90 k J/mol respectively are determined on the base of the analysis of curves of ionisation efficiency and of reaction heats Ba 2 MoO 5 =BaO+BaMoO 4 , ΔH 0 0 =322+-60 kJ/mol Ba 2 Mo 2 O 8 =2BaMoO 4 , ΔH 0 0 =351+-80 kJ/mol calculated with the use of third low of thermodynamics [ru

  16. Diarylhalotelluronium(IV) cations [(8-Me2NC10H6)2TeX]+ (X = Cl, Br, I) stabilized by intramolecularly coordinating N-donor substituents.

    Science.gov (United States)

    Beckmann, Jens; Bolsinger, Jens; Duthie, Andrew; Finke, Pamela

    2013-09-14

    The stoichiometrically controlled halogenation of the intramolecularly coordinated diaryltelluride (8-Me2NC10H6)2Te using SO2Cl2, Br2 and I2 was studied. At an equimolar ratio, the diarylhalotelluronium cations [(8-Me2NC10H6)2TeX](+) (1, X = Cl; 2, X = Br; 3, X = I) formed and were isolated as 1·Cl(-)·H21/2THF, 2·Br(-), and 3·I(-), respectively. When the same reactions were carried out in the presence of KPF6, 1·PF6(-) and 22·Br(-)·PF6(-) were obtained. The chlorination of (8-Me2NC10H6)2Te with an excess of SO2Cl2 occurred with a double electrophilic substitution at the 8-dimethylaminonaphthyl residues (in the ortho- and para-positions) and afforded the diaryltellurium dichloride (5,7-Cl2-8-Me2NC10H4)2TeCl2 (4). The bromination of (8-Me2NC10H6)2Te with three equivalents of Br2 took place with a single electrophilic substitution at the 8-dimethylaminonaphthyl residues (in the para-positions) and provided the diaryltellurium dibromide (5-Br-8-Me2NC10H5)2TeBr2 (5), while an excess of Br2 produced the diarylbromotelluronium cation [(5-Br-8-Me2NC10H5)2TeBr](+) (6) that was isolated as 6·Br3(-). The reaction of (8-Me2NC10H6)2Te with two or three equivalents of iodine provided 3·I3(-) and 3·I3(-)·I2, respectively. In the presence of water, 1·Cl(-)·H21/2THF, 2·Br(-), 3·I(-) and 3·I3(-) hydrolyzed to give the previously known diarylhydroxytelluronium cation [(8-Me2NC10H6)2TeOH](+) (7) that was isolated as 7·Cl(-), 7·Br(-)·H2O·THF, 7·I(-) and 7·I3(-)·H2O, respectively. The molecular structures of 1-7 were investigated in the solid-state by (125)Te MAS NMR spectroscopy and X-ray crystallography and in solution by multinuclear NMR spectroscopy ((1)H, (13)C, (125)Te), electrospray mass spectrometry and conductivity measurements. The stabilization of cations 1-3 by the intramolecular coordination was estimated by DFT calculations at the B3PW91/TZ level of theory.

  17. Growth Oscillatory Zoning in Erythrite, Ideally Co3(AsO4)2·8H2O: Structural Variations in Vivianite-Group Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Antao, Sytle M.; Dhaliwal, Inayat

    2017-08-01

    The crystal structure of an oscillatory zoned erythrite sample from Aghbar mine, Bou Azzer, Morocco, was refined using synchrotron high-resolution powder X-ray diffraction (HRPXRD) data, Rietveld refinement, space group C2/m, and Z = 2. The crystal contains two sets of oscillatory zones that appear to have developed during epitaxial growth. The unit-cell parameters obtained are a = 10.24799(3) Å, b = 13.42490(7) Å, c = 4.755885(8) Å, β = 105.1116(3)°, and V = 631.680(4) Å3. The empirical formula for erythrite, obtained with electron-probe micro-analysis (EPMA), is [Co2.78Zn0.11Ni0.07Fe0.04]Σ3.00(AsO4)2·8H2O. Erythrite belongs to the vivianite-type structure that contains M1O2(H2O)4 octahedra and M22O6(H2O)4 octahedral dimers that are linked by TO4 (T5+ = As or P) tetrahedra to form complex layers parallel to the (010) plane. These layers are connected by hydrogen bonds. The average O>[6] = 2.122(1) Å and average 2–O>[6] = 2.088(1) Å. With space group C2/m, there are two solid solutions: M3(AsO4)2·8H2O and M3(PO4)2·8H2O where M2+ = Mg, Fe, Co, Ni, or Zn. In these As- and P-series, using data from this study and from the literature, we find that their structural parameters evolve linearly with V and in a nearly parallel manner despite of the large difference in size between P5+ (0.170 Å) and As5+ (0.355 Å) cations. Average O>[4], O>[6], and 2–O>[6] distances increase linearly with V. The average O> distance is affected by M atoms, whereas the average O> distance is unaffected because it contains shorter and stronger P–O bonds. Although As- and P-series occur naturally, there is no structural reason why similar V-series vivianite-group minerals do not occur naturally or cannot be synthesized.

  18. Spinel LiMn 2 O 4 Nanorods as Lithium Ion Battery Cathodes

    KAUST Repository

    Kim, Do Kyung

    2008-11-12

    Spinel LiMn 2O 4 is a low-cost, environmentally friendly, and highly abundant material for Li-ion battery cathodes. Here, we report the hydrothermal synthesis of single-crystalline β-MnO 2 nanorods and their chemical conversion into free-standing single-crystalline LiMn 2O 4 nanorods using a simple solid-state reaction. The LiMn 2O 4 nanorods have an average diameter of 130 nm and length of 1.2 μm. Galvanostatic battery testing showed that LiMn 2O 4 nanorods have a high charge storage capacity at high power rates compared with commercially available powders. More than 85% of the initial charge storage capacity was maintained for over 100 cycles. The structural transformation studies showed that the Li ions intercalated into the cubic phase of the LiMn 2O 4 with a small change of lattice parameter, followed by the coexistence of two nearly identical cubic phases in the potential range of 3.5 to 4.3V. © 2008 American Chemical Society.

  19. Spinel LiMn 2 O 4 Nanorods as Lithium Ion Battery Cathodes

    KAUST Repository

    Kim, Do Kyung; Muralidharan, P.; Lee, Hyun-Wook; Ruffo, Riccardo; Yang, Yuan; Chan, Candace K.; Peng, Hailin; Huggins, Robert A.; Cui, Yi

    2008-01-01

    Spinel LiMn 2O 4 is a low-cost, environmentally friendly, and highly abundant material for Li-ion battery cathodes. Here, we report the hydrothermal synthesis of single-crystalline β-MnO 2 nanorods and their chemical conversion into free-standing single-crystalline LiMn 2O 4 nanorods using a simple solid-state reaction. The LiMn 2O 4 nanorods have an average diameter of 130 nm and length of 1.2 μm. Galvanostatic battery testing showed that LiMn 2O 4 nanorods have a high charge storage capacity at high power rates compared with commercially available powders. More than 85% of the initial charge storage capacity was maintained for over 100 cycles. The structural transformation studies showed that the Li ions intercalated into the cubic phase of the LiMn 2O 4 with a small change of lattice parameter, followed by the coexistence of two nearly identical cubic phases in the potential range of 3.5 to 4.3V. © 2008 American Chemical Society.

  20. Synthesis of LiNi0.8Co0.1Mn0.1O2 cathode material by chloride co-precipitation method

    Institute of Scientific and Technical Information of China (English)

    李灵均; 李新海; 王志兴; 伍凌; 郑俊超; 李金辉

    2010-01-01

    LiNi0.8Co0.1Mn0.1O2 was prepared by a chloride co-precipitation method and characterized by thermogravimetric analysis, X-ray diffractometry with Rietveld refinement,electron scanning microscopy and electrochemical measurements.Effects of lithium ion content and sintering temperature on physical and electrochemical performance of LiNi0.8Co0.1Mn0.1O2 were also investigated. The results show that the sample synthesized at 750℃with 105%lithium content has fine particle sizes around 200 nm and homogenous sizes distribution.The initial discharge capacity for the powder is 184 mA·h/g between 2.7 and 4.3 V at 0.1C and room temperature.

  1. Composite Ag-La0.8Sr0.2MnO3-σ Cathode for Solid Oxide Fuel Cells

    Directory of Open Access Journals (Sweden)

    Mosiałek M.

    2013-12-01

    Full Text Available Na powierzchni elektrolitu stałego wytwarzano kompozytowe katody dla stałotlenkowych ogniw paliwowych zbudowane z metalicznego srebra rozproszonego w osnowie z La0.8Sr0,3MnO3-σ Osnowę o kontrolowanej porowatości otrzymywano przez prażenie mieszaniny proszku La0.8Sr0.2MnO3-σ z kulkami z tworzywa organicznego. Porowatą osnowę nasycano roztworem AgNCb i ponownie wyprażano. Tak otrzymane katody wykazywały wyższą przewodność elektryczną i niższą oporność akty- wacyjną w reakcji redukcji tlenu w porównaniu z katodami z czystej ceramiki.

  2. Effect of MnO2 doping and temperature treatment on optical energy band gap properties in Zn-Bi-Ti-O varistor ceramics

    International Nuclear Information System (INIS)

    Ghazali, M. S. M.; Abdullah, W. R. W.; Zakaria, A.; Kamari, H. M.; Rizwan, Z.

    2016-01-01

    In this study, the optical band-gap energy ( Eg ) was investigated with respect to MnO 2 and sintering temperatures on ZnO based varistor ceramics. Eg of the ceramic (99-x) mol% ZnO + 0.5 mol% Bi 2 O 3 + 0.5 mol% TiO 2 + × MnO 2 where × = 0, 0.2, 0.4, 0.6 and 0.8 mol%, were determined using UV-Vis spectrophotometer. The samples was prepared through solid-state route and sintered at the sintering temperature from 1110, 1140 and 1170 °C for 45 and 90 min in open air. At no doping of MnO 2 , the values of Eg are 2.991 ± 0.001, 2.989 ± 0.001 eV for 45 and 90 min sintering time; respectively. Eg was decreased to 2.192 ± 0.001 eV at 1140 °C at 45 min sintering time. Similar result of Eg was observed at longer heat treatment. Further addition of dopant causing the Eg decreases rapidly to 2.099 and 2.106 ± 0.001 eV at 45 and 90 min sintering time; respectively. XRD analysis indicates that there is hexagonal ZnO and secondary phases, Zn 2 MnO 4 , Bi 4 Ti 3 O 12 and Zn 2 Ti 3 O 8 . The relative density of the sintered ceramics decreased or remain constant with the increase of MnO 2 concentration for 45 min sintering time, however, further prolong sintering time; the relative density decreases form 90.25 to 88.35%. This indicates the pores are increasing with the increase of heat treatment. The variation of sintering temperatures to the optical band gap energy of based ZnO varistor doped with MnO 2 due to the formation of interface states. (paper)

  3. 2,4-Dichloro-N-o-tolylbenzamide

    Directory of Open Access Journals (Sweden)

    Aamer Saeed

    2009-07-01

    Full Text Available In the title compound, C14H11Cl2NO, the central C—C(O—N—C amide unit makes dihedral angles of 68.71 (11 and 54.92 (12°, respectively, with the dichlorobenzene and tolyl rings. The two aromatic rings are inclined at 16.25 (17°. In the crystal, N—H...O hydrogen bonds link molecules into zigzag chains propagating in [001]. C—H...Cl contacts link these chains and additional C—H...O contacts generate stacks down b. Weak C—H...π and C—Cl...π interactions [Cl...centroid distance = 3.5422 (15 Å] may also stabilize the structure.

  4. 2,3-[(3,6-Dioxaoctane-1,8-diylbis(sulfanediylmethylene]-6,7-bis(methylsulfanyl-1,4,5,8-tetrathiafulvalene

    Directory of Open Access Journals (Sweden)

    Rui-Bin Hou

    2009-11-01

    Full Text Available In the title molecule, C16H22S8O2, two S atoms, two O atoms and ten C atoms form a 14-membered ring with a boat conformation. In the crystal, C—H...O hydrogen bonds link the molecules into dimers which are further connected into a chain along the a axis by C—H...S hydrogen bonds.

  5. Ag@Ag_8W_4O_1_6 nanoroasted rice beads with photocatalytic, antibacterial and anticancer activity

    International Nuclear Information System (INIS)

    Selvamani, Muthamizh; Krishnamoorthy, Giribabu; Ramadoss, Manigandan; Sivakumar, Praveen Kumar; Settu, Munusamy; Ranganathan, Suresh; Vengidusamy, Narayanan

    2016-01-01

    Increasing resistance of pathogens and cancer cell line towards antibiotics and anticancer agents has caused serious health problems in the past decades. Due to these problems in recent years, researchers have tried to combine nanotechnology with material science to have intrinsic antimicrobial and anticancer activity. The metals and metal oxides were investigated with respect to their antimicrobial and anticancer effects towards bacteria and cancer cell line. In the present work metal@metal tungstate (Ag@Ag_8W_4O_1_6 nanoroasted rice beads) is investigated for antibacterial activity against Escherichia coli and Staphylococcus aureus using Mueller-Hinton broth and the anticancer activity against B16F10 cell line was studied. Silver decorated silver tungstate (Ag@Ag_8W_4O_1_6) was synthesized by the microwave irradiation method using Cetyl Trimethyl Ammonium Bromide (CTAB). Ag@Ag_8W_4O_1_6 was characterized by using various spectroscopic techniques. The phase and crystalline nature were analyzed by using XRD. The morphological analysis was carried out using Field Emission Scanning Electron Microscopy (FE-SEM), and High Resolution Transmission Electron Microscopy (HR-TEM). Further, Fourier Transform Infrared Spectroscopy (FT-IR) and Raman spectral analysis were carried out in order to ascertain the presence of functional groups in Ag@Ag_8W_4O_1_6. The optical property was investigated using Diffuse Reflectance Ultraviolet–Visible Spectroscopy (DRS-UV–Vis) and the band gap was found to be 3.08 eV. Surface area of the synthesized Ag@Ag_8W_4O_1_6 wasanalyzed by BET analysis and Ag@Ag_8W_4O_1_6 was utilized for the degradation of organic dyes methylene blue and rhodamine B. The morphology of the Ag@Ag_8W_4O_1_6 resembles roasted rice beads with breath and length in nm range. The oxidation state of tungsten (W) and silver (Ag) was investigated using X-ray photoelectron spectroscopy (XPS). - Highlights: • Synthesis of Ag@Ag_8W_4O_1_6 nanoroasted rice beads using

  6. 1-(4a,8-Dimethyl-1,2,3,4,4a,5,6,8a-octahydronaphthalen-2-yl-3-(4-methylphenylprop-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Mohamed Tebbaa

    2011-06-01

    Full Text Available The title compound, C22H28O, was isolated from the aerial part of Inula viscosa (L Aiton [or Dittrichia viscosa (L Greuter]. The cyclohexene ring has a half-chair conformation, whereas the cyclohexane ring displays a chair conformation being substituted at position 2 by a 3-(4-methylphenylprop-2-enoyl group. In the crystal, weak intermolecular C—H...O hydrogen bonds link molecules into chains in the [010] direction.

  7. 2,5-Bis[(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctylsulfanyl]-1,3,4-thiadiazole

    Directory of Open Access Journals (Sweden)

    Gabriel Partl

    2017-02-01

    Full Text Available The title compound, C18H8F26N2S3, was obtained by double S-perfluorohexylethylation of dipotassium 1,3,4-thiadiazole-2,5-dithiolate in methanol. The molecule exhibits twofold rotational symmetry, with the S atom lying on the rotation axis. The fluorocarbon chains adopt helical conformations and the F atoms of the two terminal C atoms are disordered over two sets of sites. No directional intermolecular interactions occur in the crystal.

  8. High-Performance 2.6 V Aqueous Asymmetric Supercapacitors based on In Situ Formed Na0.5 MnO2 Nanosheet Assembled Nanowall Arrays.

    Science.gov (United States)

    Jabeen, Nawishta; Hussain, Ahmad; Xia, Qiuying; Sun, Shuo; Zhu, Junwu; Xia, Hui

    2017-08-01

    The voltage limit for aqueous asymmetric supercapacitors is usually 2 V, which impedes further improvement in energy density. Here, high Na content Birnessite Na 0.5 MnO 2 nanosheet assembled nanowall arrays are in situ formed on carbon cloth via electrochemical oxidation. It is interesting to find that the electrode potential window for Na 0.5 MnO 2 nanowall arrays can be extended to 0-1.3 V (vs Ag/AgCl) with significantly increased specific capacitance up to 366 F g -1 . The extended potential window for the Na 0.5 MnO 2 electrode provides the opportunity to further increase the cell voltage of aqueous asymmetric supercapacitors beyond 2 V. To construct the asymmetric supercapacitor, carbon-coated Fe 3 O 4 nanorod arrays are synthesized as the anode and can stably work in a negative potential window of -1.3 to 0 V (vs Ag/AgCl). For the first time, a 2.6 V aqueous asymmetric supercapacitor is demonstrated by using Na 0.5 MnO 2 nanowall arrays as the cathode and carbon-coated Fe 3 O 4 nanorod arrays as the anode. In particular, the 2.6 V Na 0.5 MnO 2 //Fe 3 O 4 @C asymmetric supercapacitor exhibits a large energy density of up to 81 Wh kg -1 as well as excellent rate capability and cycle performance, outperforming previously reported MnO 2 -based supercapacitors. This work provides new opportunities for developing high-voltage aqueous asymmetric supercapacitors with further increased energy density. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The oxidation of ReCl{sub 5} with oleum: synthesis and crystal structure of Re{sub 2}O{sub 4}Cl{sub 4}(SO{sub 4})

    Energy Technology Data Exchange (ETDEWEB)

    Betke, Ulf; Wickleder, Mathias S. [Carl von Ossietzky University of Oldenburg, Institute of Pure and Applied Chemistry (Germany)

    2012-01-15

    The reaction of ReCl{sub 5} and fuming sulfuric acid (25 % SO{sub 3}) in a sealed glass tube at 200 C led to red, needle shaped single crystals of Re{sub 2}O{sub 4}Cl{sub 4}(SO{sub 4}) (monoclinic, C2/c, a = 1501.8(2) pm, b = 1545.9(2) pm, c = 945.18(8) pm, β = 98.761(9) , Z = 8). In the crystal structure the [ReO{sub 2}] moieties are linked by [SO{sub 4}]{sup 2-} tetrahedra to chains along the [101] direction. Each sulfate ion connects four rhenium atoms, additional two chloride ions complete the octahedral coordination sphere of each rhenium atom according to {sup 1}{sub ∞}[ReO{sub 2/1}Cl{sub 2/1}(SO{sub 4}){sub 2/4}]. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. A fresnoite-structure-related mixed valent titanium(III/IV) chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl: A flux crystal growth route to Ti(III) containing oxides

    Energy Technology Data Exchange (ETDEWEB)

    Abeysinghe, Dileka; Smith, Mark D.; Loye, Hans-Conrad zur, E-mail: zurloye@mailbox.sc.edu

    2017-06-15

    Single crystals of mixed valent barium titanium(III/IV) chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09}, were grown in a high temperature molten chloride flux involving an in situ reduction step. The fresnoite structure related Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09} crystallizes in the tetragonal space group P4/mbm with lattice parameters of a=8.6717(2) Å, c=18.6492(5) Å. The title compound exhibits a 3D structure consisting of 2D layers of fused Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} groups and 2D layers of fused Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} groups that are linked via barium atoms. The in situ reduction of Ti(IV) to Ti(III) is achieved via the addition of metallic Mg to the flux to function as the reducing agent. The temperature dependence of the magnetic susceptibility shows simple paramagnetism above 100 K. There is a discontinuity in the susceptibility data below 100 K, which might be due to a structural change that takes place resulting in charge ordering. - Graphical abstract: The fresnoite structure related novel reduced barium titanium chlorosilicate, Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09}, were synthesized via flux method. An in situ reduction of Ti(IV) to Ti(III) achieved using Mg metal. The 3D structure consists 2D layers of fused Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} and 2D layers of fused Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} connected via barium atoms. Compound shows simple paramagnetism above 100 K. - Highlights: • The fresnoite related Ba{sub 3}Ti{sub 2}Si{sub 4}O{sub 14}Cl{sub 0.91}O{sub 0.09} were grown via molten flux method. • The in situ reduction of Ti(IV) to Ti(III) is achieved using metallic Mg. • 2D layers of Ti{sub 2}O{sub 9} and Si{sub 4}O{sub 12} and Ti{sub 2}O{sub 9}Cl{sub 2} and Si{sub 2}O{sub 7} connect via Ba atoms. • The magnetic susceptibility shows simple paramagnetism above 100 K.

  11. Impurity induced antiferromagnetic order in Haldane gap compound SrNi2-xMgxV2O8

    International Nuclear Information System (INIS)

    Pahari, B.; Ghoshray, K.; Ghoshray, A.; Samanta, T.; Das, I.

    2007-01-01

    The effect of nonmagnetic Mg 2+ doping in SrNi 2 V 2 O 8 , a Haldane gap system with a disordered ground state, was investigated using DC magnetic susceptibility and heat capacity measurements in polycrystalline samples of SrNi 2-x Mg x V 2 O 8 with x=0.03, 0.05, 0.07, 0.1 and 0.14. The results clearly reveal that the substitution of Ni 2+ (S=1) ion by Mg 2+ (S=0) ion induces a magnetic phase transition with the ordering temperatures lying in the range 3.4-4.3K, for the samples with lowest and highest value of x. The intrachain exchange constant (J/k B ) and the Haldane gap (Δ) for all the compounds were estimated to be ∼98+/-2 and 25K, respectively, which are close to that of the undoped compound. The magnetization data further suggest that the compounds exhibit metamagnetic behavior below T N , supporting a picture of antiferromagnet with significant magnetic anisotropy and competing intrachain and interchain interactions

  12. 4-Chloro-N-o-tolylbenzamide

    Directory of Open Access Journals (Sweden)

    Hiroyuki Ishida

    2008-10-01

    Full Text Available In the molecule of the title compound, C14H12ClNO, the two benzene rings are close to coplanar [dihedral angle = 7.85 (4°]. The amide N—C=O plane makes dihedral angles of 34.04 (4 and 39.90 (3°, respectively, with the 4-chloro- and 2-methylphenyl rings. In the crystal structure, intermolecular N—H...O hydrogen bonds link the molecules into chains.

  13. Diphosphine- and CO-Induced Fragmentation of Chloride-bridged Dinuclear Complex and Cp*Ir(mu-Cl)(3)Re(CO)(3) and Attempted Synthesis of Cp*Ir(mu-Cl)(3)Mn(CO)(3): Spectroscopic Data and X-ray Diffraction Structures of the Pentamethylcyclopentadienyl Compounds [Cp*IrCl{(Z)-Ph2PCH = CHPPh2}][Cl]center dot 2CHCl(3) and Cp*Ir(CO)Cl-2

    Energy Technology Data Exchange (ETDEWEB)

    Hammons, Casey [University of North Texas; Wang, Xiaoping [ORNL; Nesterov, Vladimir [University of North Texas; Richmond, Michael G. [University of North Texas

    2010-01-01

    The confacial bioctahedral compound Cp*Ir(mu-Cl)(3)Re(CO)(3) (1) undergoes rapid fragmentation in the presence of the unsaturated diphosphine ligand (Z)-Ph2PCH = CHPPh2 to give the mononuclear compounds [Cp*IrCl {(Z)-Ph2PCH = CHPPh2}][Cl] (2) and fac-ClRe(CO)(3)[(Z)-Ph2PCH = CHPPh2] (3). 2 has been characterized by H-1 and P-31 NMR spectroscopy and X-ray diffraction analysis. 2 center dot 2CHCl(3) crystallizes in the monoclinic space group C2/c, a = 35.023 (8) angstrom, b = 10.189 (2) angstrom, c = 24.003 (6) angstrom, b = 103.340 (3), V = 8,335 (3) angstrom 3, Z = 8, and d(calc) = 1.647 Mg/m(3); R = 0.0383, R-w = 0.1135 for 8,178 reflections with I> 2 sigma(I). The Ir(III) center in 2 exhibits a six-coordinate geometry and displays a chelating diphosphine group. Compound 1 reacts with added CO with fragmentation to yield the known compounds Cp*Ir(CO)Cl-2 (4) and ClRe(CO)(5) (5) in near quantitative yield by IR spectroscopy. Using the protocol established by our groups for the synthesis of 1, we have explored the reaction of [Cp*IrCl2](2) with ClMn(CO)(5) as a potential route to Cp*Ir(mu-Cl)(3)Mn(CO)(3); unfortunately, 4 was the only product isolated from this reaction. The solid-state structure of 4 was determined by X-ray diffraction analysis. 4 crystallizes in the triclinic space group P-1, a = 7.4059 (4) angstrom, b = 7.8940 (4) angstrom, c = 11.8488 (7) angstrom, alpha = 80.020 (1), beta = 79.758 (1), gamma = 68.631 (1), V = 630.34 (6) angstrom(3), Z = 2, and d(calc) = 2.246 Mg/m(3); R = 0.0126, R-w = 0.0329 for 2,754 reflections with I> 2 sigma(I). The expected three-legged piano-stool geometry in 4 has been crystallographically confirmed.

  14. Properties of spin-1/2 triangular-lattice antiferromagnets CuY2Ge2O8 and CuLa2Ge2O8

    Science.gov (United States)

    Cho, Hwanbeom; Kratochvílová, Marie; Sim, Hasung; Choi, Ki-Young; Kim, Choong Hyun; Paulsen, Carley; Avdeev, Maxim; Peets, Darren C.; Jo, Younghun; Lee, Sanghyun; Noda, Yukio; Lawler, Michael J.; Park, Je-Geun

    2017-04-01

    We found new two-dimensional (2D) quantum (S =1 /2 ) antiferromagnetic systems: Cu R E2G e2O8 (R E =Y and La). According to our analysis of high-resolution x-ray and neutron diffraction experiments, the Cu network of Cu R E2G e2O8 (R E =Y and La) exhibits a 2D triangular lattice linked via weak bonds along the perpendicular b axis. Our bulk characterizations from 0.08 to 400 K show that they undergo a long-range order at 0.51(1) and 1.09(4) K for the Y and La systems, respectively. Interestingly, they also exhibit field induced phase transitions. For theoretical understanding, we carried out the density functional theory (DFT) band calculations to find that they are typical charge-transfer-type insulators with a gap of Eg≅2 eV . Taken together, our observations make Cu R E2G e2O8 (R E =Y and La) additional examples of low-dimensional quantum spin triangular antiferromagnets with the low-temperature magnetic ordering.

  15. (S-(−-1-Phenylethanaminium 4-(4,4-difluoro-1,3,5,7-tetramethyl-3a,4a-diaza-4-borata-s-indacen-8-ylbenzoate

    Directory of Open Access Journals (Sweden)

    Lindsay M. Hinkle

    2011-09-01

    Full Text Available The title compound, C8H12N+·C20H18BF2N2O2−, crystallizes with a significant amount of void space [4.0 (5%] in the unit cell. The structure displays N—H...O hydrogen bonding between the components. The plane formed by the benzoic acid moiety of the BODIPY-CO2− is twisted by 80.71 (6° relative to the plane formed by the ring C and N atoms of the tetramethyldipyrrin portion of the molecule.

  16. 6-Chloro-3-[5-(3-methoxy-8-methyl-4-quinolyl-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl]-2-methyl-4-phenylquinoline

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2009-11-01

    Full Text Available In the title compound, C36H29ClN4O, the dihydropyrazole ring adopts an envelope conformation. The two quinoline ring systems (r.m.s. deviations = 0.029 and 0.018 Å are oriented at a dihedral angle of 71.43 (4°. One of the quinoline rings makes a dihedral angle of 65.40 (7° with the phenyl substituent. In the crystal, molecules are linked into chains along the b axis by intermolecular C—H...N hydrogen bonds. In addition, C—H...π and π–π [centroid–centroid distance = 3.7325 (8 Å] interactions are observed.

  17. Methyl 11-hydroxy-9-[1-(4-methoxyphenyl-4-oxo-3-phenoxyazetidin-2-yl]-18-oxo-10-oxa-2-azapentacyclo[9.7.0.01,8.02,6.012,17]octadeca-12(17,13,15-triene-8-carboxylate

    Directory of Open Access Journals (Sweden)

    S. Sundaramoorthy

    2012-07-01

    Full Text Available In the title compound, C34H32N2O8, one of the pyrrolidine rings in the pyrrolizidine ring system adopts a twist conformation, whereas the other ring adopts an envelope conformation (C atom as flap. The five-membered ring in the indene ring system and the fused furan ring also adopt envelope conformations (C and O atoms as flaps, respectively. The β-lactam ring makes dihedral angles of 23.41 (2 and 25.98 (2°, respectively, with the attached methoxyphenyl and phenoxy rings. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond, generating an S(5 motif. In the crystal, molecules are linked into C(12 chains running along the a axis by C—H...O hydrogen bonds. The structure is further consolidated by weak intermolecular C—H...π and π–π interactions [centroid–centroid distance = 3.7987 (14 Å].

  18. Coupling between magnetic, dielectric properties and crystal structure in MnT2O4 (T = V, Cr, Mn)

    International Nuclear Information System (INIS)

    Suzuki, T; Adachi, K; Katsufuji, T

    2006-01-01

    We measured the temperature dependence of dielectric constant and striction for spinel MnT 2 O 4 (T = V, Cr, Mn) under magnetic field. We found critical changes of the dielectric constant and striction with ferrimagnetic ordering as well as applied magnetic field in MnV 2 O 4 and Mn 3 O 4 , which have orbital degree of freedom in the T 3+ ion. This result indicates the importance of the orbital degree of freedom for the coupling between dielectric, magnetic properties and crystal structure in these spinel compounds

  19. Crystal structure of hexakis(dimethyl sulfoxide-κO)manganese(II) tetraiodide

    KAUST Repository

    Haque, Mohammed; Davaasuren, Bambar; Rothenberger, Alexander; Wu, Tao

    2016-01-01

    The title salt, [Mn(C2H6OS)6]I4, is made up from discrete [Mn(DMSO)6]2+ (DMSO is dimethyl sulfoxide) units connected through non-classical hydrogen bonds to linear I4 2- tetraiodide anions. The MnII ion in the cation, situated on a position with site symmetry -3., is octahedrally coordinated by O atoms of the DMSO molecule with an Mn - O distance of 2.1808(12)Å. The I4 2- anion contains a neutral I2 molecule weakly coordinated by two iodide ions, forming a linear centrosymmetric tetraiodide anion. The title compound is isotypic with the Co, Ni, Cu, and Zn analogues.

  20. Crystal structure of hexakis(dimethyl sulfoxide-κO)manganese(II) tetraiodide

    KAUST Repository

    Haque, Mohammed

    2016-11-15

    The title salt, [Mn(C2H6OS)6]I4, is made up from discrete [Mn(DMSO)6]2+ (DMSO is dimethyl sulfoxide) units connected through non-classical hydrogen bonds to linear I4 2- tetraiodide anions. The MnII ion in the cation, situated on a position with site symmetry -3., is octahedrally coordinated by O atoms of the DMSO molecule with an Mn - O distance of 2.1808(12)Å. The I4 2- anion contains a neutral I2 molecule weakly coordinated by two iodide ions, forming a linear centrosymmetric tetraiodide anion. The title compound is isotypic with the Co, Ni, Cu, and Zn analogues.

  1. Nano-sized Mn3O4 and β-MnOOH from the decomposition of β-cyclodextrin-Mn: 2. The water-oxidizing activities.

    Science.gov (United States)

    Najafpour, Mohammad Mahdi; Mostafalu, Ramin; Hołyńska, Małgorzata; Ebrahimi, Foad; Kaboudin, Babak

    2015-11-01

    Nano-sized Mn oxides contain Mn3O4, β-MnOOH and Mn2O3 have been prepared by a previously reported method using thermal decomposition of β-cyclodextrin-Mn complexes. In the next step, the water-oxidizing activities of these Mn oxides using cerium(IV) ammonium nitrate as a chemical oxidant are studied. The turnover frequencies for β-MnO(OH) and Mn3O4 are 0.24 and 0.01-0.17 (mmol O2/mol Mns), respectively. Subsequently, water-oxidizing activities of these compounds are compared to the other previously reported Mn oxides. Important factors affecting water oxidation by these Mn oxides are also discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Syntheses, crystal structures, and properties of the isotypic pair [Cr(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O and [In(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Van, Nguyen-Duc; Kleeberg, Fabian M.; Schleid, Thomas [Institut fuer Anorganische Chemie, Universitaet Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart (Germany)

    2015-11-15

    Single crystals of [Cr(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O and [In(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O were obtained by reactions of aqueous solutions of the acid (H{sub 3}O){sub 2}[B{sub 12}H{sub 12}] with chromium(III) hydroxide and indium metal shot, respectively. The title compounds crystallize isotypically in the trigonal system with space group R anti 3c (a = 1157.62(3), c = 6730.48(9) pm for the chromium, a = 1171.71(3), c = 6740.04(9) pm for the indium compound, Z = 6). The arrangement of the quasi-icosahedral [B{sub 12}H{sub 12}]{sup 2-} dianions can be considered as stacking of two times nine layers with the sequence..ABCCABBCA.. and the metal trications arrange in a cubic closest packed..abc.. stacking sequence. The metal trications are octahedrally coordinated by six water molecules of hydration, while another fifteen H{sub 2}O molecules fill up the structures as zeolitic crystal water or second-sphere hydrating species. Between these free and the metal-bonded water molecules, bridging hydrogen bonds are found. Furthermore, there is also evidence of hydrogen bonding between the anionic [B{sub 12}H{sub 12}]{sup 2-} clusters and the free zeolitic water molecules according to B-H{sup δ-}..{sup δ+}H-O interactions. Vibrational spectroscopy studies prove the presence of these hydrogen bonds and also show slight distortions of the dodecahydro-closo-dodecaborate anions from their ideal icosahedral symmetry (I{sub h}). Thermal decomposition studies for the example of [Cr(H{sub 2}O){sub 6}]{sub 2}[B{sub 12}H{sub 12}]{sub 3}.15H{sub 2}O gave no hints for just a simple multi-stepwise dehydration process. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Crystal structure of (1S,2R,6R,7R,8S,12S-4,10,17-triphenyl-15-thia-4,10-diazapentacyclo[5.5.5.01,16.02,6.08,12]heptadeca-13,16-diene-3,5,9,11-tetrone p-xylene hemisolvate

    Directory of Open Access Journals (Sweden)

    Wayland E. Noland

    2014-12-01

    Full Text Available The title tetrone compound, C32H22N2O4S· 0.5C8H10, is the major product (50% yield of an attempted Diels–Alder reaction of 2-(α-styrylthiophene with N-phenylmaleimide (2 equivalents in toluene. Recrystallization of the resulting powder from p-xylene gave the title hemisolvate; the p-xylene molecule is located about an inversion center. In the crystal, the primary tetrone contacts are between a carbonyl O atom and the four flagpole H atoms of the bicyclo[2.2.2]octene core, forming chains along [001].

  4. 4,10-Diallyloxy-1,2,3,6b,7,8,9,12b-octahydroperylene

    Directory of Open Access Journals (Sweden)

    Terrill D. Smith

    2010-01-01

    Full Text Available In the title compound, C26H28O2, the central atoms are coplanar, with the –CH2—CH2– links of the cyclohexene groups lying to either side of the plane and with the diallyloxy residues twisted out of this plane [C—C—O—C torsion angles = 16.6 (3 and −13.9 (3°]. In the crystal structure, molecules are connected into chains propagating in [100] via C—H...π interactions.

  5. Preparation, characteristics and electrochemical properties of surface-modified LiMn2O4 by doped LiNi0.05Mn1.95O4

    International Nuclear Information System (INIS)

    Yuan, Y.F.; Wu, H.M.; Guo, S.Y.; Wu, J.B.; Yang, J.L.; Wang, X.L.; Tu, J.P.

    2008-01-01

    The surface-modified spinel LiMn 2 O 4 by doped LiNi 0.05 Mn 1.95 O 4 was prepared by a tartaric acid gel method. Transmission electron microscope (TEM) images indicated that some small particles with 100-200 nm in diameter modified the surface of large particle LiMn 2 O 4 . Energy dispersive spectrometry (EDS) showed that the particles were LiNi 0.05 Mn 1.95 O 4 . Electrochemical properties of LiNi 0.05 Mn 1.95 O 4 -modified spinel LiMn 2 O 4 were intensively investigated by the galvanostatic charge-discharge tests, cyclic voltammetry (CV) and AC impedance measurements. The doped LiNi 0.05 Mn 1.95 O 4 -modified LiMn 2 O 4 cathode delivered the same initial discharge capacity as the unmodified LiMn 2 O 4 , but its cyclic stability was evidently improved, the capacity retention ratio reached 96% after 20 cycles, being higher than 89% of the unmodified LiMn 2 O 4 . Cyclic voltammograms of the LiNi 0.05 Mn 1.95 O 4 -modified LiMn 2 O 4 did not markedly change while the semicircle diameter of AC impedance spectra evidently decreased after 20 cycles, which showed that the surface modification with LiNi 0.05 Mn 1.95 O 4 improved the electrochemical activity and cycling stability of LiMn 2 O 4 .

  6. The effect of MgO doping on the structure, magnetic and magnetotransport properties of La0.8Sr0.2MnO3 composite

    International Nuclear Information System (INIS)

    Aezami, A.; Eshraghi, M.; Kameli, P.; Salamati, H.

    2007-01-01

    Full text: The recent observation of anomalously Colossal Magnetoresistance (CMR) in the La 1-x A x MnO 3 (A = Sr, Ca, Ba or vacancies) system, has spurred renewed interest in studying these doped perovskite manganites. The properties of these materials are explained by double exchange theory of Zener and electron lattice interaction. However, the intrinsic CMR effect in the perovskite manganites is found on a magnetic field scale of several teslas and a narrow temperature range. It was found that, the presence of grain boundaries in polycrystalline samples leads to a large Low Field Magnetoresistance (LFMR) effect over a wide temperature range below the Curie temperature Tc. To achieve LFMR, different properties are considered. One of them is mixing of these CMR materials with secondary insulator phases. In this work, La 0.8 Sr 0.2 MnO 3 (LSMO) was selected as matrix material and MgO as a dopant. The La 0.8 Sr 0.2 MnO 3/x MgO samples with x= 0, 1, 2, 3, 5 and 7.5 Wt.% were prepared by Solid State Reaction method. Studies show that most part of the MgO goes into the perovskite lattice and Mg substituted Mn in LSMO and remainder segregates as a separate phase at the grain boundaries. Results also show that the value of MR decreases for all the doping levels. It seems that, due to the almost same ionic radii of Mg2+ and Mn2+, and at the higher sintering temperature, Mg2+ mostly replaced Mn3+ and weakens double exchange interaction. This speculation has been confirmed by XRD, SEM, susceptibility, resistivity and magnetoresistance analysis and measurements. (authors)

  7. Resistance switching mechanism of La{sub 0.8}Sr{sub 0.2}MnO{sub 3−δ} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Luo, X.D. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Gao, R.L., E-mail: gaorongli2008@163.com [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Fu, C.L.; Cai, W.; Chen, G.; Deng, X.L. [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing 401331 (China); Zhang, H.R; Sun, J.R. [Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Science, Beijing 100190 (China)

    2016-02-15

    Effects of oxygen vacancies on the electrical transport properties of oxygen stoichiometric La{sub 0.8}Sr{sub 0.2}MnO{sub 3} and oxygen-deficient La{sub 0.8}Sr{sub 0.2}MnO{sub 3−δ} films have been investigated. The result presents that the oxygen-deficient films annealed in vacuum show obvious increase of resistance and lattice parameter. With the sweeping voltage or temperature increasing, the resistance exhibits obvious bipolar switching effect, no forming process was needed. Oxygen deficiency in the annealed film leads to the formation of a structural disorder in the Mn–O–Mn conduction channel due to the accumulation of oxygen vacancies under high external electric field or temperatures and hence is believed to be responsible for the bipolar resistance switching effect and the enhanced resistivity compared with oxygen stoichiometric La{sub 0.8}Sr{sub 0.2}MnO{sub 3} film. These results may be important for practical applications in photoelectric or storage devices and point to a useful direction for other oxidizing materials.

  8. Tris(2,2′-bipyridine-κ2 N,N′)cobalt(III) bis­[bis­(pyridine-2,6-dicarboxyl­ato-κ3 O 2,N,O 6)cobaltate(III)] perchlorate dimethyl­formamide hemisolvate 1.3-hydrate

    Science.gov (United States)

    Golenya, Irina A.; Boyko, Alexander N.; Kotova, Natalia V.; Haukka, Matti; Iskenderov, Turganbay S.

    2012-01-01

    In the title compound, [Co(C10H8N2)3][Co(C7H3NO4)2]2(ClO4)·0.5C3H7NO·1.3H2O, the CoIII atom in the complex cation is pseudoocta­hedrally coordinated by six N atoms of three chelating bipyridine ligands. The CoIII atom in the complex anion is coordinated by two pyridine N atoms and four carboxyl­ate O atoms of two doubly deprotonated pyridine-2,6-dicarboxyl­ate ligands in a distorted octa­hedral geometry. One dimethyl­formamide solvent mol­ecule and two water mol­ecules are half-occupied and one water mol­ecule is 0.3-occupied. O—H⋯O hydrogen bonds link the water mol­ecules, the perchlorate anions and the complex anions. π–π inter­actions between the pyridine rings of the complex anions are also observed [centroid–centroid distance = 3.804 (3) Å]. PMID:23125573

  9. Magnetic characterization of Nd0.8Sr0.2(Mn1-x Co x )O3 perovskites

    International Nuclear Information System (INIS)

    Vidal, Karmele; Lezama, Luis; Arriortua, Maria I.; Rojo, Teofilo; Gutierrez, Jon; Barandiaran, Jose M.

    2005-01-01

    We present a magnetic study of the family of perovskites Nd 0.8 Sr 0.2 (Mn 1- x Co x )O 3 (x=0.1, 0.2 and 0.3). These compositions have been prepared by using both the sol-gel method and the freeze-drying technique. As a result, we have obtained polycrystalline powder-like samples. We have obtained pure compounds that have been indexed in the Pnma space group. The study of their magnetic properties shows a decrease of the measured low-temperature magnetic moment as the content of Co increases in the composition. However, a similar magnetic ordering temperature of about 130 K has been determined for all samples. All the studied compounds show insulating behaviour of the electrical resistivity

  10. Insulators containing CuCl4X22- (X=H2O, NH3) units: Origin of the orthorhombic distortion observed only for CuCl4(H2O)22-

    DEFF Research Database (Denmark)

    García-Fernández, P.; García Lastra, Juan Maria; Trueba, A.

    2012-01-01

    The origin of the difference in structure between compounds containing CuCl4X22- (X=H2O, NH3) units is analyzed by means of first-principles calculations. While NH3-containing compounds display tetragonal symmetry, H2O-containing ones display an orthorhombic distortion at low temperature where...... the equatorial Cl- ions are no longer equivalent. Our simulations of optical and vibrational transitions show good agreement with all available experimental optical absorption and Raman data. As a salient feature, the value of the force constant for the B1g mode, K(B1g), driving the orthorhombic distortion......CuCl4(H2O)2 has a local origin....

  11. Quaternary system LiF-LiCl-LiVO3-Li2MoO4

    International Nuclear Information System (INIS)

    Anipchenko, B.V.; Garkushin, I.K.

    2000-01-01

    Interactions in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system are studied by differential thermal analysis. Rate of heating/cooling of the samples comprised 15 Grad/min, mass of sample composed 0.2 g. The system was investigated in the 300-650 Deg C range. X-ray diffraction method was used for determination of purity of the reagents. Composition and temperature of quaternary component eutectics are determined: 16.5 mol. % of LiF, 47.0 mol. % of LiCl, 28.8 mol. % of LiVO 3 , 7.6 mol. % of Li 2 MoO 4 ; 387 Deg C. Mean value of melting enthalpy of quaternary eutectics mixture in the LiF-LiCl-LiVO 3 -Li 2 MoO 4 system on the results of the tests was in the range of 222 kJ/kg [ru

  12. Colossal thermoelectric power factor in K7/8RhO2

    KAUST Repository

    Saeed, Yasir

    2012-04-12

    The thermoelectric properties of the layered oxides KxRhO 2 (x = 1/2 and 7/8) are investigated by means of the electronic structure, as determined by ab inito calculations and Boltzmann transport theory. In general, the electronic structure of K xRhO 2 is similar to Na xCoO 2, but with strongly enhanced transport. K 7/8RhO 2 exceeds the ultrahigh power factor of Na 0.88CoO 2 reported previously by more than 50%. The roles of the cation concentration and the lattice parameters in the transport properties in this class of compounds are explained. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. No-carrier-added (NCA) synthesis of 6-[18F]fluoro-L-DOPA using 3,5,6,7,8,8a-hexahydro-7,7,8a-trimethyl-[6S-(6α, 8α, 8αβ)]-6,8-methano-2H-1,4-benzoxazin-2-one

    International Nuclear Information System (INIS)

    Horti, A.; Yale Univ., West Haven, CT; Redmond, D.E. Jr.; Soufer, R.

    1995-01-01

    3,5,6,7,8,8a-Hexahydro-7,7,8a-trimethyl-[6S-(6α,8α , 8αβ)]-6,8-methano-2H-1,4-benzoxazino-2-one (2) was investigated as chiral auxiliary for asymmetric NCA nucleophilic synthesis of 6-[ 18 F]Fluoro-L-DOPA. Direct condensation of 3,4-dimethoxy-2-[ 18 F]fluorobenzaldehyde (1a) or 6-[ 18 F]fluoro-piperonal (1b) in the presence of NaH with 2 gave the corresponding [ 18 F]-3-[(2-fluorophenyl)methylene]-3,5,6,7,8,8a-hexahydro-7,7,8 a-trimethyl-[6S-(3Z,3α,6α,8α,8αβ)]-6, 8-methano-2H-1,4-benzoxazin-2-one derivative 3a or 3b as a single stereoisomer. L-Selectride promoted hydrogenation of the olefinic double bond of these derivatives, in presence of tertbutyl alcohol, afforded the corresponding [ 18 F]-3-[(2-fluorophenyl) methyl]-3,5,6,7,8,8a-hexahydro-7,7,8a-trimethyl-[3S-(3α, 6α, 8α8αβ)]-6,8-methano-2H-1,4-benzoxazin-2-one derivatives (4a,b) without affecting the orientation of diasterofacial discrimination. Deprotection of the derivatives 4a,b yielded 6-[ 18 F]fluoro-L-DOPA (e.e. >90%, 3% radiochemical yield (EOB), total synthesis time 125 min, specific activity >2000 mCi/μmol). Direct deprotection/reduction of the compounds 3a,b provides the enantiomeric mixture of 6-[ 18 F]fluoro-D,L-DOPA (10-12% radiochemical yield) and, after chiral separation, 6-[ 18 F]fluoro-L-DOPA (e.e. 98%, 4-5% radiochemical yield). (author)

  14. Two actinide-organic frameworks constructed by a tripodal flexible ligand: Occurrence of infinite ((UO{sub 2})O{sub 2}(OH){sub 3}){sub 4n} and hexanuclear (Th{sub 6}O{sub 4}(OH){sub 4}) motifs

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Lingling; Zhang, Ronglan [College of Chemistry and Materials, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of education, Northwest University, Xi’an 710069 (China); Zhao, Jianshe, E-mail: jszhao@nwu.edu.cn [College of Chemistry and Materials, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of education, Northwest University, Xi’an 710069 (China); Liu, Chiyang, E-mail: lcy@nwu.edu.cn [Department of Geology, Northwest University, Xi’an 710069 (China); Weng, Ng Seik [The University of Nottingham Malaysia Campus, 43500 Semenyih, Selangor Darul Ehsan (Malaysia)

    2016-11-15

    Two new actinide metal-organic frameworks were constructed by using a tripodal flexible ligand tris (2-carboxyethyl) isocyanurate (H{sub 3}tci) under hydrothermal condition. The combination of H{sub 3}tci and uranyl nitrate hexahydrate in aqueous solution leads to the isolation of [(UO{sub 2}){sub 2}(H{sub 2}O){sub 4}]{sub 0.5}(tci){sub 2}(UO{sub 2}){sub 4}(OH){sub 4}·18H{sub 2}O (1), which contains two distinct UO{sub 2}{sup 2+} coordination environments. Four uranyl cations, linked through μ{sub 3}-OH respectively, result in the edge-sharing ribbons. Then, the layer structure is constructed by U-O clusters linked through other eight-coordinated uranyl unions, giving rise to a porous structure in the space. Topological analysis reveals that complex 1 belongs to a (4, 8)-connected net with a schläfli symbol of (3{sup 4.}2{sup 6.}3){sub 2}(3{sup 4.}4{sup 6.}5{sup 6.}6{sup 8.}7{sup 3.}8). Th{sub 3}(tci){sub 2}O{sub 2}(OH){sub 2}(H{sub 2}O){sub 3}·12H{sub 2}O (2) generated by the reaction of H{sub 3}tci and thorium nitrate tetrahydrate, possesses nine-fold coodinated Th(IV) centers with a monocapped square antiprismatic geometry. The hexamers “Th{sub 6}O{sub 4}(OH){sub 4}” motifs are connected together by the carboxylate groups, showing a three-dimensional structures. Complex 2 takes on an 8-connected architecture and the point symbol is (4{sup 24.}6{sup 4}). - Graphical abstract: Two new 3D actinide metal-organic frameworks were constructed by using a tripodal flexible ligand tris (2-carboxyethyl) isocyanurate (H3tci) and their topological structures were displayed. The infinite ((UO{sub 2})O{sub 2}(OH){sub 3}){sub 4n} and hexanuclear (Th{sub 6}O{sub 4}(OH){sub 4}) motifs were found in the title actinides networks.

  15. Apparent molar volumes for dilute solutions of NaClO4 and [Co(en) 3](ClO4)3 in D2O and H2O at 278-318 K

    International Nuclear Information System (INIS)

    Bottomley, G.A.; Glossop, L.G.

    1981-01-01

    Apparent molar volumes for dilute solutions of NaClO 4 and [Co(en) 3 ](ClO 4 ) 3 in D 2 O and H 2 O were measured by using a dilatometry technique at 278, 298 and 318K. Comparison of limiting slopes with the Debye-Huckel predictions from the dielectric constant and compressibility of H 2 O and D 2 O is complicated by ion pairing. The apparent molar volumes for NaClO 4 were less in D 2 O than in H 2 O. The complex [Co(en) 3 ](ClO 4 ) 3 when studied in D 2 O had its amine protons exchanged by deuterium; this did not allow a direct comparison of the apparent molar volumes of the protonated complex in each solvent system, but revealed a large isotope effect. The apparent molar volumes of the [Co(en) 3 ](ClO 4 ) 3 showed a much larger temperature dependence than that of NaClO 4

  16. Tris[2,2,6,6-tetramethyl-8-(trimethylsilylbenzo[1,2-d;4,5-d′]bis(1,3-dithiol-4-yl]methanol diethyl ether monosolvate

    Directory of Open Access Journals (Sweden)

    Nico Fleck

    2018-04-01

    Full Text Available The title compound, a triarylmethanol, C46H64OS12Si3 1, was synthesized via lithiation of tris-2,2,6,6-tetramethylbenzo[1,2-d;4,5-d′]bis[1,3]dithiol-4-yl-methanol, 2, and electrophilic quenching with trimethylsilyl chloride. The current crystal structure reveals information about the reactivity of this compound and compares well with the structure reported for the unsubstituted parent compound 2 [Driesschaert et al. (2012. Eur. J. Org. Chem. 33, 6517–6525]. The title compound 1 forms molecular propellers and crystallizes in P\\overline{1}, featuring an unusually long Si—Car bond of 1.910 (3 Å. Moreover, the geometry at the central quaternary carbon is rather trigonal-pyramidal than tetrahedral due to vast intramolecular stress. One trimethylsilyl group is disordered over two positions in a 0.504 (4:0.496 (4 ratio and one S atom is disordered over two positions in a 0.509 (7:0.491 (7 ratio. The contribution of disordered diethyl ether solvent molecule(s was removed using the PLATON SQUEEZE (Spek, 2015 solvent masking procedure. These solvent molecules are not considered in the given chemical formula and other crystal data.

  17. Monodisperse MnO2@NiCo2O4 core/shell nanospheres with highly opened structures as electrode materials for good-performance supercapacitors

    Science.gov (United States)

    Zhou, You; Ma, Li; Gan, Mengyu; Ye, Menghan; Li, Xiurong; Zhai, Yanfang; Yan, Fabing; Cao, Feifei

    2018-06-01

    The monodisperse MnO2@NiCo2O4 core/shell nanospheres for good-performance supercapacitors are designed and synthesized by a two-step solution-based method and a simple post annealing process. In the composite, both MnO2 (the "core") and NiCo2O4 (the "shell") are formed by the accumulation of nanoflakes. Thus, nearly all the core/shell nanoflakes are highly opened and accessible to electrolyte, making them give full play to the Faradaic reaction. Our results demonstrate that the composite electrode exhibits desirable pseudocapacitive behaviors with higher specific capacitance (1127.27 F g-1 at a current density of 1 A g-1), better rate capability (81.0% from 1 to 16 A g-1) and superior cycling stability (actually 126.8% capacitance retention after 1000 cycles and only 3.7% loss after 10,000 cycles at 10 A g-1) in 3 M KOH aqueous solution. Moreover, it offers the excellent specific energy density of 26.6 Wh kg-1 at specific power density of 800 W kg-1. The present MnO2@NiCo2O4 core/shell nanospheres with remarkable electrochemical properties are considered as potential electrode materials for the next generation supercapacitors.

  18. Flexible Asymmetric Solid-State Supercapacitors by Highly Efficient 3D Nanostructured α-MnO2 and h-CuS Electrodes.

    Science.gov (United States)

    Patil, Amar M; Lokhande, Abhishek C; Shinde, Pragati A; Lokhande, Chandrakant D

    2018-05-16

    A simplistic and economical chemical way has been used to prepare highly efficient nanostructured, manganese oxide (α-MnO 2 ) and hexagonal copper sulfide (h-CuS) electrodes directly on cheap and flexible stainless steel sheets. Flexible solid-state α-MnO 2 /flexible stainless steel (FSS)/polyvinyl alcohol (PVA)-LiClO 4 /h-CuS/FSS asymmetric supercapacitor (ASC) devices have been fabricated using PVA-LiClO 4 gel electrolyte. Highly active surface areas of α-MnO 2 (75 m 2 g -1 ) and h-CuS (83 m 2 g -1 ) electrodes contribute to more electrochemical reactions at the electrode and electrolyte interface. The ASC device has a prolonged working potential of +1.8 V and accomplishes a capacitance of 109.12 F g -1 at 5 mV s -1 , energy density of 18.9 Wh kg -1 , and long-term electrochemical cycling with a capacity retention of 93.3% after 5000 cycles. Additionally, ASC devices were successful in glowing seven white-light-emitting diodes for more than 7 min after 30 s of charging. Outstandingly, real practical demonstration suggests "ready-to-sell" products for industries.

  19. Neutron diffraction and low temperature magnetization study of Tb0.8Y0.2MnO3

    International Nuclear Information System (INIS)

    Chakraborty, Keka R.; Mukadam, M.; Yusuf, S.M.; Shukla, R.; Tyagi, A.K.; Kaushik, S.D.; Siruguri, V.

    2012-01-01

    Multiferroic materials possess mutually correlated magnetic and electric order parameters which are suitable for device applications but scarcity of such materials and the separation of magnetic and electric ordering temperatures are a major hindrance in technological applications. TbMnO 3 is one of the material which is reported to have higher magnetoelectric coupling. Structurally, TbMnO 3 crystallizes in orthorhombically distorted perovskite structure (space group Pbnm). For TbMnO 3 , several reports are available in the literature which further modify the magnetoelectric coupling by selective doping or reducing the particle size to nano dimensions, or preparing thin films. Here, we study the effect of Y doping at Tb site in nanoparticle form in terms of crystal structure and magnetic properties. Nanoparticles of Tb 0.8 Y 0.2 MnO 3 were synthesized using the gel combustion technique. Crystal structure of this sample is studied at 300 K using neutron diffraction

  20. Hexatungstate subunit as building block in the hydrothermal synthesis of organic-inorganic hybrid materials: synthesis, structure and optical properties of Co2(bpy)6 (W6O19)2 (bpy=4,4'-bipyridine)

    International Nuclear Information System (INIS)

    Zhang Lijuan; Wei Yongge; Wang Chongchen; Guo Hongyou; Wang Ping

    2004-01-01

    A hydrothermal reaction of WO 3 , CoCl 2 and 4,4'-bipyridine, yields a novel organic-inorganic hybrid compound, Co 2 (bpy) 6 (W 6 O 19 ) 2 , at 170 deg. C. X-ray single crystal structure determination reveals a two-dimensional covalent structure belonging to monoclinic crystal system, space group C2/c, with cell parameters a=19.971(4) A, b=11.523(2) A, c=16.138(3) A, β=96.49(3) deg., V=3690.0 A 3 and Z=2. The hexatungstate, [W 6 O 19 ] 2- , acts as a building block in bidentate fashion to bridge the Co(II) centers in the crystal structure. The title compound is found to have an optical energy gap of 2.2 eV from UV-Vis-NIR reflectance spectra

  1. A heptadecanuclear Mn(III)9Dy(III)8 cluster derived from triethanolamine with two edge sharing supertetrahedra as the core and displaying SMM behaviour.

    Science.gov (United States)

    Langley, Stuart K; Moubarakia, Boujemaa; Murray, Keith S

    2010-06-07

    A heterometallic, heptadecanuclear cluster of formula [Mn(III)9Dy(III)8O8(OH)8(tea)2(teaH)2(teaH2)4(Ac)4(NO3)2(H2O)4](NO3)7·8H2O (1) is reported. The core of 1 displays two edge sharing Mn(III)5Dy(III)5 supertetrahedra and represents one of the largest Mn/4f cluster compound so far reported. Magnetic studies show that 1 displays probable SMM behaviour as observed via non-zero values in the χM''vs T plot.

  2. Observation of spin reorientation in layered manganites La1.2Sr1.8(Mn1-yRuy)2O7 (0.0=2) by Lorentz transmission electron microscopy

    International Nuclear Information System (INIS)

    Yu, X.Z.; Uchida, M.; Onose, Y.; He, J.P.; Kaneko, Y.; Asaka, T.; Kimoto, K.; Matsui, Y.; Arima, T.; Tokura, Y.

    2006-01-01

    The effect of Ru substitution for Mn in bilayered oxides La 1.2 Sr 1.8 (Mn 1-y Ru y ) 2 O 7 (0= for the y=0 crystal to the c-axis for y=0.2, and it rotates away from the c-axis for the y=0.05 and y=0.07 crystals with decreasing temperature. Furthermore, maze-shaped magnetic domain structures were observed in the (001) thin crystals with 0.05=< y=<0.2. Changes in domain size and structure indicate that the uniaxial magnetic anisotropy becomes stronger as Ru content y increases

  3. 6,7-Dichloro-3-(2,4-dichlorobenzylquinoxalin-2(1H-one

    Directory of Open Access Journals (Sweden)

    Jinpeng Zhang

    2012-08-01

    Full Text Available In the title compound, C15H8Cl4N2O, the quinoxaline ring system is almost planar, with a dihedral angle between the benzene and pyrazine rings of 3.1 (2°. The 2,4-dichlorophenyl ring is approximately perpendicular to the pyrazine ring, with a dihedral angle of 86.47 (13° between them. The crystal packing features intermolecular N—H...O hydrogen bonds and π–π stacking interactions, with centroid–centroid distances in the range 3.699 (3–4.054 (3 Å.

  4. Synthesis and properties of A{sub 6}B{sub 2}(OH){sub 16}Cl{sub 2}.4H{sub 2}O (A = Mg, Ni, Zn, Co, Mn and B = Al, Fe) materials for environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Anderson, E-mail: anderson_dias@iceb.ufop.br [Departamento de Quimica, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, ICEB II, Sala 67, Ouro Preto-MG, 35400-000 (Brazil); Cunha, Lumena; Vieira, Andiara C. [Departamento de Quimica, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, ICEB II, Sala 67, Ouro Preto-MG, 35400-000 (Brazil)

    2011-09-15

    Highlights: {yields} A{sub 6}B{sub 2}(OH){sub 16}Cl{sub 2}.4H{sub 2}O (A = Mg, Ni, Zn, Co, Mn and B = Al, Fe) materials were synthesized. {yields} Chemical synthesis produced different levels of crystallinity and ordering degree. {yields} Structural investigation by Raman scattering revealed a complex band structure. {yields} A strong correlation between band structure and ionic radius was determined. -- Abstract: Double layered hydroxide materials of composition A{sub 6}B{sub 2}(OH){sub 16}Cl{sub 2}.4H{sub 2}O (A = Mg, Ni, Zn, Co, Mn and B = Al, Fe) were synthesized by chemical precipitation at 60 {sup o}C. Different levels of crystallinity and ordering degree were observed depending upon the chemical environment or the combination between divalent and trivalent cations. The results from high-resolution transmission electron microscopy revealed that nanostructured layered samples were obtained with interplanar spacing compatible with previous literature. Raman scattering was employed to investigate the complex band structure observed, particularly the lattice vibrations at lower frequencies, which is intimately correlated to the cationic radius of both divalent and trivalent ions. The results showed that strongly coordinated water and chloride ions besides highly structured hydroxide layers have a direct influence on the stability of the hydrotalcites. It was observed that transition and decomposition temperatures varied largely for different chemical compositions.

  5. Investigation of magnetic transitions through ultrasonic measurements in double-layered CMR manganite La1.2Sr1.8Mn2O7

    Science.gov (United States)

    Reddy, Y. S.; Vishnuvardhan Reddy, C.

    2014-03-01

    A polycrystalline, double-layered, colossal magnetoresistive manganite La1.2Sr1.8Mn2O7 is synthesized by sol-gel process and its magnetic and ultrasonic properties were investigated in the temperature range 80-300 K. The sample has Curie temperature at 124 K, where the sample exhibits a transition from paramagnetic insulator to ferromagnetic metallic state. The longitudinal sound velocity measurements show a significant hardening of sound velocity below TC, which may be attributed to the coupling between ferromagnetic spins and longitudinal acoustic phonons. The magnetization and ultrasonic studies reveal the presence of secondary transition at ≈ 260 K in this sample. The present sound velocity measurement results confirm the reliability of ultrasonic investigations as an independent tool to probe magnetic transitions in manganites.

  6. Pressure-induced colossal piezoresistance effect and the collapse of the polaronic state in the bilayer manganite (La0.4Pr0.6)1.2Sr1.8Mn2O7

    International Nuclear Information System (INIS)

    Thiyagarajan, R; Manivannan, N; Arumugam, S; Esakki Muthu, S; Tamilselvan, N R; Yoshino, H; Murata, K; Sekar, C; Apostu, M O; Suryanarayanan, R; Revcolevschi, A

    2012-01-01

    We have investigated the effect of hydrostatic pressure as a function of temperature on the resistivity of a single crystal of the bilayer manganite (La 0.4 Pr 0.6 ) 1.2 Sr 1.8 Mn 2 O 7 . Whereas a strong insulating behaviour is observed at all temperatures at ambient pressure, a clear transition into a metallic-like behaviour is induced when the sample is subjected to a pressure (P) of ∼1.0 GPa at T 6 in the low temperature region at moderate pressures is observed. When the pressure is increased further (5.5 GPa), the high temperature polaronic state disappears and a metallic behaviour is observed. The insulator to metal transition temperature exponentially increases with pressure and the distinct peak in the resistivity that is observed at 1.0 GPa almost vanishes for P > 7.0 GPa. A modification in the orbital occupation of the e g electron between 3d x 2 -y 2 and 3d z 2 -r 2 states, as proposed earlier, leading to a ferromagnetic double-exchange phenomenon, can qualitatively account for our data. (paper)

  7. Poly[[diaqua-μ4-pyrazine-2,3-dicarboxylato-κ6N,O2:O2′:O3,O3′:O3-strontium(II] monohydrate

    Directory of Open Access Journals (Sweden)

    Vahid Amani

    2008-07-01

    Full Text Available In the title compound, {[Sr(C6H2N2O4(H2O2]·H2O}n, the SrII ions are bridged by the pyrazine-2,3-dicarboxylate ligands with the formation of two-dimensional polymeric layers parallel to the ac plane. Each SrII ion is eight-coordinated by one N and five O atoms from the four ligands and two water molecules. The coordination polyhedron is derived from a pentagonal bipyramid with an O atom at the apex on one side of the equatorial plane and two O atoms sharing the apical site on the other side. The coordinated and uncoordinated water molecules are involved in O—H...O and O—H...N hydrogen bonds, which consolidate the crystal structure.

  8. Tetrakis(6-methyl-2,2′-bipyridine-1κ2N,N′;2κ2N,N′;3κ2N,N′;4κ2N,N′-tetra-μ-nitrato-1:2κ2O:O′;2:3κ3O:O′,O′′;2:3κ3O,O′:O′′;3:4κ2O:O′-tetranitrato-1κ4O,O′;4κ2O,O′-tetralead(II

    Directory of Open Access Journals (Sweden)

    Roya Ahmadi

    2009-10-01

    Full Text Available In the tetranuclear centrosymmetric title compound, [Pb4(NO38(C11H10N24], irregular PbN2O5 and PbN2O4 coordination polyhedra occur. The heptacoordinated lead(II ion is bonded to two bidentate and one monodentate nitrate ion and one bidentate 6-methyl-2,2′-bipyridine (mbpy ligand. The six-coordinate lead(II ion is bonded to one bidentate and two monodentate nitrate anions and one mbpy ligand. In the crystal, bridging nitrate anions lead to infinite chains propagating in [111]. A number of C—H...O hydrogen bonds may stabilize the structure.

  9. Fe3O4 and MnO2 assembled on honeycomb briquette cinders (HBC) for arsenic removal from aqueous solutions.

    Science.gov (United States)

    Zhu, Jin; Baig, Shams Ali; Sheng, Tiantian; Lou, Zimo; Wang, Zhuoxing; Xu, Xinhua

    2015-04-09

    In this study, a novel composite adsorbent (HBC-Fe3O4-MnO2) was synthesized by combining honeycomb briquette cinders (HBC) with Fe3O4 and MnO2 through a co-precipitation process. The purpose was to make the best use of the oxidative property of MnO2 and the adsorptive ability of magnetic Fe3O4 for enhanced As(III) and As(V) removal from aqueous solutions. Experimental results showed that the adsorption capacity of As(III) was observed to be much higher than As(V). The maximum adsorption capacity (2.16 mg/g) was achieved for As(III) by using HBC-Fe3O4-MnO2 (3:2) as compared to HBC-Fe3O4-MnO2 (2:1) and HBC-Fe3O4-MnO2 (1:1). The experimental data of As(V) adsorption fitted well with the Langmuir isotherm model, whereas As(III) data was described perfectly by Freundlich model. The pseudo-second-order kinetic model was fitted well for the entire adsorption process of As(III) and As(V) suggesting that the adsorption is a rate-controlling step. Aqueous solution pH was found to greatly affect the adsorption behavior. Furthermore, co-ions including HCO3(-) and PO4(3-) exhibited greater influence on arsenic removal efficiency, whereas Cl(-), NO3(-), SO4(2-) were found to have negligible effects on arsenic removal. Five consecutive adsorption-regeneration cycles confirmed that the adsorbent could be reusable for successive arsenic treatment and can be used in real treatment applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Enhanced microwave absorption properties of MnO{sub 2} hollow microspheres consisted of MnO{sub 2} nanoribbons synthesized by a facile hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Han, Bingqian; Chen, Nan; Deng, Dongyang; Guan, Hongtao [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Wang, Yude, E-mail: ydwang@ynu.edu.cn [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Yunnan Province Key Lab of Micro-Nano Materials and Technology, Yunnan University, 650091, Kunming (China)

    2016-08-15

    MnO{sub 2} hollow microspheres consisted of nanoribbons were successfully fabricated via a facile hydrothermal method with SiO{sub 2} sphere templates. The crystal structure, morphology and microwave absorption properties in X and Ku band of the as-synthesized samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and a vector network analyzer. The results show that the three-dimensional (3D) hollow microspheres are assembled by ultra thin and narrow one-dimensional (1D) nanoribbons. A rational process for the formation of hollow microspheres is proposed. The 3D MnO{sub 2} hollow microspheres possess improved dielectric and magnetic properties than the 1D nanoribbons prepared by the same procedures with the absence of SiO{sub 2} hard templates, which are closely related to their special nanostructures. The MnO{sub 2} microspheres also show much better microwave absorption properties in X (812 GHz) and Ku (12–18 GHz) microwave band compared with 1D MnO{sub 2} nanoribbons. The minimum reflection loss of −40 dB for hollow microsphere can be observed at 14.2 GHz and reflection loss below −10 dB is 3.5 GHz with a thickness of only 4 mm. The possible mechanism for the enhanced microwave absorption properties is also discussed. - Graphical abstract: MnO{sub 2} hollow microspheres composed of nanoribbons show the excellent microwave absorption properties in X and Ku band. - Highlights: • MnO{sub 2} hollow microspheres consisted of MnO{sub 2} nanoribbons were successfully prepared. • MnO{sub 2} hollow microspheres possess good microwave absorption performances. • The excellent microwave absorption properties are in X and Ku microwave band. • Electromagnetic impedance matching is great contribution to absorption properties.

  11. [N,N-Bis(2-aminoethylethane-1,2-diamine](ethane-1,2-diaminenickel(II thiosulfate trihydrate

    Directory of Open Access Journals (Sweden)

    Beatrix Seidlhofer

    2012-02-01

    Full Text Available The title compound, [Ni(C2H8N2(C6H18N4]S2O3·3H2O, was accidentally synthesized under solvothermal conditions applying [Ni(en3]Cl2 (en is ethane-1,2-diamine as the Ni source. The asymmetric unit consists of one discrete [Ni(tren(en]2+ complex [tren is N,N-bis(2-aminoethylethane-1,2-diamine] in which the Ni2+ cation is sixfold coordinated within a slightly distorted octahedron, one thiosulfate anion and three water molecules. In the crystal, the complex cations, anions and water molecules are linked by an intricate hydrogen-bonding network. One C atom of the tren ligand, as well as one O atom of a water molecule, are disordered over two sites and were refined using a split model (occupancy ratios = 0.85:15 and 0.60:0.40, respectively.

  12. Preparation and characterization of La/sub 2/TiMnO/sub 6/

    Energy Technology Data Exchange (ETDEWEB)

    Ramanujachary, K V; Swamy, C S [Indian Inst. of Tech., Madras. Dept. of Chemistry

    1981-01-01

    The compound La/sub 2/TiMnO/sub 6/ has been prepared by solid state reaction of the component ions in suitable form. X-ray analysis shows it to be orthorhombic and the cell constants are a = 5.506 A, b = 5.950 A and c = 7.636 A. It is found to be essentially a p-type semiconductor with ..cap alpha.. = 150 ..mu..VKsup(-1). Weiss constant has a value -88K and it shows IR bands at 400-450 and 575-600 cmsup(-1) characteristic of ..nu../sub 3/ and ..nu../sub 4/ modes of the Tisup(4+) O/sub 6/ octahedra.

  13. Enhanced permanganate in situ chemical oxidation through MnO2 particle stabilization: evaluation in 1-D transport systems.

    Science.gov (United States)

    Crimi, Michelle; Quickel, Mark; Ko, Saebom

    2009-02-27

    In situ chemical oxidation using permanganate is an increasingly employed approach to organic contaminant remediation at hazardous waste sites. Manganese dioxide (MnO2) particles form as a by-product of the reaction of permanganate with contaminants and naturally-reduced subsurface materials. These particles are of interest because they have the potential to deposit in the subsurface and impact the flow regime in/around permanganate injection, including the well screen, filter pack, and the surrounding subsurface formation. Control of these particles can allow for improved oxidant injection and transport, and contact between the oxidant and contaminants of concern. Sodium hexametaphosphate (HMP) has previously been identified as a promising aid to stabilize MnO2 in solution when included in the oxidizing solution, increasing the potential to inhibit particle deposition and impact subsurface flow. The goal of the experimental studies described herein was to investigate the ability of HMP to prevent particle deposition in transport studies using four different types of porous media. Permanganate was delivered to a contaminant source zone (trichloroethylene) located within four different media types with variations in sand, clay, organic carbon, and iron oxides (as goethite) content. Deposition of MnO2 within the columns was quantified with distance from the source zone. Experiments were repeated in replicate columns with the inclusion of HMP directly with the oxidant delivery solution, and MnO2 deposition was again quantified. While total MnO2 deposition within the 60 cm columns did not change significantly with the addition of HMP, deposition within the contaminant source zone decreased by 25-85%, depending on the specific media type. The greatest differences in deposition were observed in the goethite-containing and clay-containing columns. Columns containing these two media types experienced completely plugged flow in the oxidant-only delivery systems; however

  14. Tritium release in Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Linjie, E-mail: zhaolinjie1989@163.com; Long, Xinggui, E-mail: xingguil@caep.cn; Peng, Shuming, E-mail: pengshuming@caep.cn; Chen, Xiaojun; Xiao, Chengjian; Ran, Guangming; Li, Jiamao

    2016-12-15

    Li{sub 4+x}Si{sub 1−x}Al{sub x}O{sub 4} solid solution materials, which were designed as the advanced tritium breeders, were obtained by indirect solid state reactions. The behaviors of tritium release from Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} powders were investigated by temperature programmed desorption. The tritium release curves show different characteristics for the Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} ceramics. The main tritium release peak in the Li{sub 4}SiO{sub 4} and Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} powders is at approximately 600 °C after a high dose irradiation. Moreover, the temperature of the tritium release from Li{sub 4.2}Si{sub 0.8}Al{sub 0.2}O{sub 4} was lower than that of the release from Li{sub 4}SiO{sub 4}. This suggests a possible advantage to using the solid solutions as the advanced tritium breeding materials.

  15. CL from ZnO nanowires and microneedles Co-doped with N and Mn

    International Nuclear Information System (INIS)

    Herrera, M; Morales, A; Díaz, J A

    2014-01-01

    Cathodoluminescence (CL) was used to study the luminescence emission of ZnO : N, Mn nanowires and microneedles grown by thermal evaporation. CL spectra acquired at room temperature showed the presence of near band edge and defect-related emissions. The defect related emission comprised two bands centered at 2.28 and 2.5 eV. The first component was attributed to the formation of spinel ZnMn 2 O 4  and the second to the well-known ZnO green emission. CL spectra acquired at 100 K showed two emissions centered at 3.22 and 3.25 eV that were attributed to donor–acceptor pair (DAP) and FA transitions, respectively. It was proposed that substitutional nitrogen (N O ) and zinc interstitial (Zn i ) were acceptor and shallow-donor centers in the DAP transition. (paper)

  16. A new solid solution compound with the Sr{sub 21}Mn{sub 4}Sb{sub 18} structure type. Sr{sub 13}Eu{sub 8}Cd{sub 3}Mn{sub 1}Sb{sub 18}

    Energy Technology Data Exchange (ETDEWEB)

    Kunz Wille, Elizabeth L.; Cooley, Joya A.; Fettinger, James C.; Kazem, Nasrin; Kauzlarich, Susan M. [California Univ., Davis, CA (United States). Dept. of Chemistry

    2017-09-01

    The title compound with the nominal formula, Sr{sub 13}Eu{sub 8}Cd{sub 3}Mn{sub 1}Sb{sub 18}, was synthesized by Sn-flux. Structure refinement was based on single-crystal X-ray diffractometer data. Employing the exact composition, the formula is Sr{sub 13.23}Eu{sub 7.77}Cd{sub 3.12}Mn{sub 0.88}Sb{sub 18} for the solid solution Sr{sub 21-x}Eu{sub x}Cd{sub 4-y}Mn{sub y}Sb{sub 18}. This phase adopts the Sr{sub 21}Mn{sub 4}Sb{sub 18} type structure with site preferences for both Eu and Cd. The structure crystallizes in the monoclinic system in space group C2/m and Z=4: a=18.1522(11), b=17.3096(10), c=17.7691(10) Aa, β=91.9638(8) , 6632 F{sup 2} values, 216 variables, R1=0.0254 and wR2=0.0563. Site selectivity of the elements in this new compound will be discussed in relationship with the Sr{sub 21}Mn{sub 4}Sb{sub 18} type structure and other related structure types. Temperature dependent magnetic susceptibility data reveal Curie-Weiss paramagnetism with an experimental moment of 19.3 μ{sub B}/f.u. and a Weiss constant of 0.4 K. Magnetic ordering is seen at low temperatures, with a transition temperature of 3.5 K.

  17. Poly[[aqua(μ2-4,4′-bipyridine-κ2N:N′[μ3-3-bromo-2-(carboxylatomethylbenzoato-κ3O1:O1′:O2]cadmium] monohydrate

    Directory of Open Access Journals (Sweden)

    Yangmei Liu

    2012-08-01

    Full Text Available In the title compound, {[Cd(C9H5BrO4(C10H8N2(H2O]·H2O}n, the CdII atom has a distorted octahedral coordination geometry. Two N atoms from two 4,4′-bipyridine (bipy ligands occupy the axial positions, while the equatorial positions are furnished by three carboxylate O atoms from three 3-bromo-2-(carboxylatomethylbenzoate (bcb ligands and one O atom from a water molecule. The bipy and bcb ligands link the CdII atoms into a three-dimensional network. O—H...O hydrogen bonds and π–π interactions between the pyridine and benzene rings [centroid–centroid distance = 3.736 (4 Å] are present in the crystal.

  18. Molten salt synthesis of La0.8Sr0.2MnO3 powders for SOFC cathode electrode

    Science.gov (United States)

    Gu, Sin-il; Shin, Hyo-soon; Hong, Youn-woo; Yeo, Dong-hun; Kim, Jong-hee; Nahm, Sahn; Yoon, Sang-ok

    2012-08-01

    For La0.8Sr0.2MnO3 (LSM) perovskite, used as the cathode material for solid oxide fuel cells (SOFC), it is known that the formation of a triple-phase-boundary is restrained due to the formation of a second phase at the YSZ/electrode interface at high temperature. To decrease the 2nd phase, lowering the sintering temperature has been used. LSM powder was synthesized by molten salt synthesis method to control its particle size, shape, and agglomeration. We have characterized the phase formation, particle size, shape, and sintering behavior of LSM in the synthesis using the variation of KCl, LiCl, KF and its mixed salts as raw materials. In the case of KCl and KCl-KF salts, the particle size and shape of the LSM was well controlled and synthesized. However, in the case of LiCl and KCl-LiCl salts, LiMnOx as 2nd phase and LSM were synthesized simultaneously. In the case of the mixed salt of KCl-KF, the growth mechanism of the LSM particle was changed from `diffusion-controlled' to `reaction-controlled' according to the amount of mixed salt. The sintering temperature can be decreased below 1000 °C by using the synthesized LSM powder.

  19. High-pressure BaCrO_3 polytypes and the 5H–BaCrO_2_._8 phase

    International Nuclear Information System (INIS)

    Arévalo-López, Angel M.; Paul Attfield, J.

    2015-01-01

    Polytypism of BaCrO_3 perovskites has been investigated at 900–1100 °C and pressures up to 22 GPa. Hexagonal 5H, 4H, and 6H perovskites are observed with increasing pressure, and the cubic 3C perovskite (a=3.99503(1) Å) is observed in bulk form for the first time at 19–22 GPa. An oxygen-deficient material with limiting composition 5H–BaCrO_2_._8 is synthesised at 1200 °C under ambient pressure. This contains double tetrahedral Cr"4"+ layers and orders antiferromagnetically below 260 K with a (0 0 1/2) magnetic structure. - Graphical abstract: Hexagonal 5H, 4H, and 6H perovskites polytypes of BaCrO_3 are observed with increasing pressure and the cubic 3C perovskite is stabilised in bulk form for the first time at 19–22 GPa. Oxygen-deficient 5H–BaCrO_2_._8 synthesised at ambient pressure contains double tetrahedral Cr"4"+ layers and orders antiferromagnetically below 260 K with a (0 0 1/2) magnetic structure.

  20. Crystal structure and magnetic properties of the Cr-doped spiral antiferromagnet BiMnFe{sub 2}O{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Batuk, Dmitry, E-mail: Dmitry.batuk@ua.ac.be [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp (Belgium); De Dobbelaere, Christopher [Inorganic and Physical Chemistry Group, Hasselt University, Institute for Materials Research, Agoralaan Building D, B-3590, Diepenbeek (Belgium); Tsirlin, Alexander A. [National Institute of Chemical Physics and Biophysics, 12618, Tallinn (Estonia); Abakumov, Artem M. [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp (Belgium); Hardy, An; Van Bael, Marlies K. [Inorganic and Physical Chemistry Group, Hasselt University, Institute for Materials Research, Agoralaan Building D, B-3590, Diepenbeek (Belgium); IMEC vzw, Division IMOMEC, Agoralaan Building D, B-3590, Diepenbeek (Belgium); Greenblatt, Martha [Department of Chemistry and Chemical Biology, Rutgers, State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey, 08854-8087 (United States); Hadermann, Joke [Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerp (Belgium)

    2013-09-01

    Graphical abstract: - Highlights: • The substitution of Cr for Mn in BiMnFe{sub 2}O{sub 6} is possible by the solution–gel method. • The BiCr{sub x}Mn{sub 1−x}Fe{sub 2}O{sub 6} solid solution is obtained for the x values up to 0.3. • Increasing Cr content lowers the temperature of the antiferromagnetic ordering. - Abstract: We report the Cr{sup 3+} for Mn{sup 3+} substitution in the BiMnFe{sub 2}O{sub 6} structure. The BiCr{sub x}Mn{sub 1−x}Fe{sub 2}O{sub 6} solid solution is obtained by the solution–gel synthesis technique for the x values up to 0.3. The crystal structure investigation using a combination of X-ray powder diffraction and transmission electron microscopy demonstrates that the compounds retain the parent BiMnFe{sub 2}O{sub 6} structure (for x = 0.3, a = 5.02010(6)Å, b = 7.06594(7)Å, c = 12.6174(1)Å, S.G. Pbcm, R{sub I} = 0.036, R{sub P} = 0.011) with only a slight decrease in the cell parameters associated with the Cr{sup 3+} for Mn{sup 3+} substitution. Magnetic susceptibility measurements suggest strong similarities in the magnetic behavior of BiCr{sub x}Mn{sub 1−x}Fe{sub 2}O{sub 6} (x = 0.2; 0.3) and parent BiMnFe{sub 2}O{sub 6}. Only T{sub N} slightly decreases upon Cr doping that indicates a very subtle influence of Cr{sup 3+} cations on the magnetic properties at the available substitution rates.

  1. Poly[[aqua(μ5-3,4,5,6-tetracarboxycyclohexane-1,2-dicarboxylatostrontium] monohydrate

    Directory of Open Access Journals (Sweden)

    Pei-Chi Cheng

    2011-12-01

    Full Text Available In the title compound, {[Sr(C12H10O12(H2O]·H2O}n, the SrII ion is coordinated by six O atoms of five symmetry-related 3,4,5,6-tetracarboxycyclohexane-1,2-dicarboxylate ligands and one water molecule in a slightly distorted monocapped trigonal–prismatic environment. The ligands bridge the SrII ions, forming a two-dimensional structure. In the crystal, O—H...O hydrogen bonds further connect the structure into a three-dimensional network. The H atoms of two of the carboxyl groups were refined as half-occupancy.

  2. Aqua(4-hydroxypyridine-2,6-dicarboxylato(1,10-phenanothrolinecopper(II 4.5-hydrate

    Directory of Open Access Journals (Sweden)

    Hossein Aghabozorg

    2008-01-01

    Full Text Available The title compound, [Cu(C7H3NO5(C12H8N2(H2O4.5H2O or [Cu(hypydc(phen(H2O4.5H2O (phen is 1,10-phenanthroline and hypydcH2 is 4-hydroxypyridine-2,6-dicarboxylic acid, was obtained by the reaction of copper(II nitrate hexahydrate with the proton-transfer compound (phenH2(hypydc in aqueous solution. Both the cationic and the anionic fragments of the proton-transfer compound are involved in complexation. Each CuII atom has a distorted octahedral geometry. It is hexacoordinated by three O atoms and three N atoms, from one phen fragment (as bidentate ligand, one (hypydc2− unit (as tridentate ligand and a water molecule. In the crystal structure, O—H...O and C—H...O hydrogen bonds, and π–π stacking interactions [centroid-to-centroid distance 3.5642 (11 Å] between the phen ring systems, contribute to the formation of a three-dimensional supramolecular structure.

  3. Synthesis and structural studies on cerium substituted La0.4Ca0.6MnO3 as solid oxide fuel cell electrode material

    Science.gov (United States)

    Singh, Monika; Kumar, Dinesh; Singh, Akhilesh Kumar

    2018-04-01

    For solid oxide fuel cell electrode material, calcium doped lanthanum manganite La0.4Ca0.6MnO3 (LCMO) and cerium-incorporated on Ca-site with composition La0.40Ca0.55Ce0.05MnO3 (LCCMO) were synthesized using most feasible and efficient glycine-nitrate method. The formation of crystalline single phase was confirmed by x-ray diffraction (XRD). The Rietveld analysis reveals that both systems crystallize into orthorhombic crystal structure with Pnma space group. Additionally, 8 mole % Y2O3 stabilized ZrO2 (8YSZ) solid electrolyte was also synthesized using high energy ball mill to check the reaction with electrode materials. It was found that the substitution of Ce+4 cations in LCMO perovskite suppressed formation of undesired insulating CaZrO3 phase.

  4. Ammonia Uptake and Release in the MnX2–NH3 (X = Cl, Br Systems and Structure of the Mn(NH3nX2 (n = 6, 2 Ammines

    Directory of Open Access Journals (Sweden)

    Duncan H. Gregory

    2012-04-01

    Full Text Available Hexa-ammine complexes, Mn(NH36X2 (X = Cl, Br, have been synthesized by ammoniation of the corresponding transition metal halide and characterized by Powder X-ray diffraction (PXRD and Raman spectroscopy. The hexa-ammine complexes are isostructural (Cubic, Fm-3m, Z = 4; a = 10.2742(6 Å and 10.527(1 Å for X = Cl, Br respectively. Temperature programmed desorption (TPD demonstrated that ammonia release from Mn(NH36X2 complexes occurred in three stages corresponding to the release of 4, 1 and 1 NH3 equivalents respectively. The chloride and bromide both exhibit a deammoniation onset temperature below 323 K. The di-ammoniates from the first desorption step were isolated during TPD measurements and their crystal structures determined by Rietveld refinement against PXRD data (X = Cl: orthorhombic Cmmm, a = 8.1991(9 Å, b = 8.2498(7 Å, c = 3.8212(4 Å, Z = 2; X = Br: orthorhombic Pbam, a = 6.0109(5 Å, b = 12.022(1 Å, c = 4.0230(2 Å, Z = 2.

  5. Synthesis, crystal structure and photoluminescence of a new Eu-doped Sr containing sialon (Sr{sub 0.94}Eu{sub 0.06})(Al{sub 0.3}Si{sub 0.7}){sub 4}(N{sub 0.8}O{sub 0.2}){sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Hisanori, E-mail: yamane@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Shimooka, Satoshi; Uheda, Kyota [Mitsubishi Chemical Group, Science and Technology Research Center, Inc. 1000 Kamoshida-cho, Aoba-ku, Yokohama 227-8502 (Japan)

    2012-06-15

    Colorless transparent platelet single crystals of a novel Eu{sup 2+}-doped strontium silicon aluminum oxynitride, (Sr{sub 0.94}Eu{sub 0.06})(Al{sub 0.3}Si{sub 0.7}){sub 4}(N{sub 0.8}O{sub 0.2}){sub 6}, were prepared at 1800 Degree-Sign C and 0.92 MPa of N{sub 2}. Fundamental reflections of electron and X-ray diffraction of the crystals were indexed with a face-centered orthorhombic unit cell (a=5.8061(5) A, b=37.762(3) A, c=9.5936(9) A). Diffuse streaks elongated in the b-axis direction were observed around the fundamental reflections hkl with h=2n+1 of the electron and X-ray diffraction, indicating stacking faults of (0 1 0)[1 0 0]/2. A crystal structure model without the stacking faults was obtained using the X-ray diffraction data of the fundamental reflections with the space group Fdd2. A SiN{sub 4}-tetrahedron double layer of [SiN{sub 2}]{sub 2} and a Sr/Eu double layer of [(Sr{sub 0.94}Eu{sub 0.06})Al{sub 1.2}Si{sub 0.8}N{sub 0.8} O{sub 1.2}]{sub 2} are stacked alternately along the b-axis direction. The title compound showed an emission with a peak wavelength of 490 nm under 334 nm excitation at room temperature. - Graphical abstract: Single crystals of a novel Eu{sup 2+}-doped strontium silicon aluminum oxynitride, (Sr{sub 0.94}Eu{sub 0.06})(Al{sub 0.3}Si{sub 0.7}){sub 4}(N{sub 0.8}O{sub 0.2}){sub 6}, having stacking faults on the (0 1 0) plane of an orthorhombic cell, were prepared at 1800 Degree-Sign C and 0.92 MPa of N{sub 2}. The compound showed emission with a peak wavelength of 490 nm under 334 nm excitation at room temperature. Highlights: Black-Right-Pointing-Pointer A new compound Eu{sup 2+}-doped (Sr{sub 0.94}Eu{sub 0.06})(Al{sub 0.3}Si{sub 0.7}){sub 4}(N{sub 0.8}O{sub 0.2}){sub 6} was prepared. Black-Right-Pointing-Pointer Stacking faults in the compound were clarified by electron and X-ray diffraction. Black-Right-Pointing-Pointer A basic crystal structure model was obtained based on the X-ray diffraction data. Black-Right-Pointing-Pointer An

  6. Crystal structure of triaqua(1,10-phenanthroline-κ2N,N′(2,4,5-trifluoro-3-methoxybenzoato-κO1cobalt(II 2,4,5-trifluoro-3-methoxybenzoate

    Directory of Open Access Journals (Sweden)

    Junshan Sun

    2014-11-01

    Full Text Available The title salt, [Co(C8H4F3O3(C12H8N2(H2O3](C8H4F3O3, was obtained under solvothermal conditions by the reaction of 2,4,5-trifluoro-3-methoxybenzoic acid with CoCl2 in the presence of 1,10-phenanthroline (phen. The CoII ion is octahedrally coordinated by two N atoms [Co—N = 2.165 (2 and 2.129 (2 Å] from the phen ligand, by one carboxylate O atom [Co—O = 2.107 (1 Å] and by three O atoms from water molecules [Co—O = 2.093 (1, 2.102 (1 and 2.114 (1 Å]. The equatorial positions of the slightly distorted octahedron are occupied by the N atoms, the carboxylate O and one water O atom. An intra- and intermolecular O—H...O hydrogen-bonding network between the water-containing complex cation and the organic anion leads to the formation of ribbons parallel to [010].

  7. Butane-1,4-diammonium bis(pyridine-2,6-dicarboxylato-κ3O2,N,O6cadmate(II dihydrate

    Directory of Open Access Journals (Sweden)

    Najmeh Firoozi

    2008-10-01

    Full Text Available In the title compound, (C4H14N2[Cd(C7H3NO42]·2H2O, the CdII ion is coordinated by four O atoms [Cd—O = 2.2399 (17–2.2493 (17 Å] and two N atoms [Cd—N = 2.3113 (15 and 2.3917 (15 Å] from two tridentate pyridine-2,6-dicarboxylato ligands in a distorted octahedral geometry. The uncoordinated water molecules are involved in O—H...O and N—H...O hydrogen bonds, which contribute to the formation of a three-dimensional supramolecular structure, along with π–π stacking interactions [centroid–centroid distances of 3.5313 (13 and 3.6028 (11 Å between the pyridine rings of neighbouring dianions].

  8. Effect of MnCuFe{sub 2}O{sub 4} content on magnetic and dielectric properties of poly (O-Phenylenediamine)/MnCuFe{sub 2}O{sub 4} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kannapiran, Nagarajan [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Muthusamy, Athianna, E-mail: muthusrkv@gmail.com [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India); Chitra, Palanisamy [PG and Research Department of Chemistry, Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore 641020, Tamil Nadu (India)

    2016-03-01

    Poly o-phenylenediamine (PoPD)/MnCuFe{sub 2}O{sub 4} nanocomposites with three different ratios of MnCuFe{sub 2}O{sub 4} (10%, 20%, 30% w/w) were synthesized by in-situ oxidative chemical polymerization method ammonium persulphate used as oxidant, while MnCuFe{sub 2}O{sub 4} nanoparticles was prepared by auto-combustion method. The structure, morphology and magnetic properties of synthesized PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites were characterized by FT-IR, UV–visible absorption spectra, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and Vibrating sample magnetometer (VSM). FTIR spectra and XRD were confirmed the formation of the PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites. The morphology of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites is visualized through SEM and TEM. The spherical morphology of the PoPD was confirmed using SEM analysis. Dielectric properties of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites at different temperatures have been performed in the frequency range of 50 Hz–5 MHz. The optical absorption experiments of PoPD/MnCuFe{sub 2}O{sub 4} nanocomposites reveal that the direct transition with an energy band gap is around 2 eV. - Highlights: • Green synthesis of PoPD (the polymerization carried out only in aqueous medium) by in-situ chemical polymerization method. • For the first time, PoPD incorporated with MnCuFe{sub 2}O{sub 4} with lesser particle size. • The auto combustion reaction, support to achieve less particle size. • Ferrite content affects the magnetic properties of the nanocomposites.

  9. Study on lithium extraction from brines based on LiMn2O4/Li1-xMn2O4 by electrochemical method

    International Nuclear Information System (INIS)

    Zhao, Meng-Yao; Ji, Zhi-Yong; Zhang, Yong-Guang; Guo, Zhi-Yuan; Zhao, Ying-Ying; Liu, Jie; Yuan, Jun-Sheng

    2017-01-01

    Highlights: •A recovery system with LiMn 2 O 4 /Li 1-x Mn 2 O 4 as electrodes was used to extract lithium. •The influence sequence of coexisting ions on lithium extraction was Mg 2+ > Na + > Ca 2+ > K + . •The values of α Li-Na , α Li-Mg and α Li-Ca were more than 300, 70 and 110, respectively. •The specific energy consumption was between 18 and 19 W h·mol −1 . -- Abstract: Lithium rechargeable batteries have been used for lithium extraction in recent years. Here, we report on a highly selective lithium recovery system that consists of a LiMn 2 O 4 positive electrode, a Li 1-x Mn 2 O 4 negative electrode and a monovalent selective anion-exchange membrane. The effect of potential, temperature and coexisting ions on lithium extraction were investigated in this paper, and the lithium recovery system was applied to extract lithium from brine and concentrated seawater. The extraction capacity of Li + reached 34.31 mg· (1 g LiMn 2 O 4 ) −1 at 1.2 V. With higher reaction rate and lower energy consumption, 25 °C (room temperature) was considered as the appropriate temperature. The system still remained high selective for Li + even in the presence of impurity ions (K + , Na + , Mg 2+ , Ca 2+ ). With simulated brine and concentrated seawater as source solutions, the concentrations of Na + , Mg 2+ and Ca 2+ were reduced more than 300, 70 and 100 times, consuming 18–19 W h per mole of lithium recovered. And the electrodes still had high separation coefficients of Li + and Me n+ (Na + , Mg 2+ , Ca 2+ ) after five cycles although a slight drop was existing.

  10. 4-Bromoanilinium perchlorate 18-crown-6 clathrate

    Directory of Open Access Journals (Sweden)

    Min Guo

    2010-11-01

    Full Text Available The reaction of 4-bromoaniline, 18-crown-6, and perchloric acid in methanol yields the title compound, C6H7BrN+·ClO4−·C12H24O6, in which the protonated –NH3+ group forms three bifurcated N—H...O hydrogen bonds to the O atoms of the crown ether.

  11. Structural phase transition and multiferroic properties of Bi0.8A0.2Fe0.8Mn0.2O3 (A = Ca, Sr)

    Science.gov (United States)

    Rout, Jyoshna; Choudhary, R. N. P.

    2018-05-01

    The multiferroic BiFeO3 and Bi0.8A0.2Fe0.8Mn0.2O3 (A = Ca, Sr) have been synthesized using direct mechanosynthesis. Detailed investigations were made on the influence of Ca-Mn and Sr-Mn co-substitutions on the structure change, electric and magnetic properties of the BFO. Rietveld refinement on the XRD pattern of the modified samples clarifies the structural transition from R3c:H (parent BiFeO3) to the biphasic structure (R3c: H + Pnma). Scanning electron micrographs confirmed the polycrystalline nature of the materials and each of the microstructure comprised of uniformly distributed grains with less porosity. The dielectric measurements reveal that enhancement in dielectric properties due to the reduction of oxygen vacancies by substitutional ions. Studies of frequency-dependence of impedance and related parameters exhibit that the electrical properties of the materials are strongly dependent on temperature, and bear a good correlation with its microstructure. The bulk resistance (evaluated from impedance studies) is found to decrease with increasing temperature for all the samples. The alternating current (ac) conductivity spectra show a typical signature of an ionic conducting system, and are found to obey Jonscher's universal power law. Preliminary studies of magnetic characteristics of the samples reveal enhanced magnetization for Ca-Mn co-substituted sample. The magnetoelectric coefficient as the function of applied dc magnetizing field under fixed ac magnetic field 15.368 Oe is measured and this ME coefficient αME corresponds to induction of polarization by a magnetic field.

  12. No-carrier-added (NCA) synthesis of 6-[{sup 18}F]fluoro-L-DOPA using 3,5,6,7,8,8a-hexahydro-7,7,8a-trimethyl-[6S-(6{alpha}, 8{alpha}, 8{alpha}{beta})]-6,8-methano-2H-1,4-benzoxazin-2-one

    Energy Technology Data Exchange (ETDEWEB)

    Horti, A. [Yale Univ., New Haven, CT (United States). School of Medicine]|[Yale Univ., West Haven, CT (United States). PET Center; Redmond, D.E. Jr. [Yale Univ., New Haven, CT (United States). School of Medicine; Soufer, R. [Yale Univ., West Haven, CT (United States). PET Center

    1995-12-31

    3,5,6,7,8,8a-Hexahydro-7,7,8a-trimethyl-[6S-(6{alpha},8{alpha} , 8{alpha}{beta})]-6,8-methano-2H-1,4-benzoxazino-2-one (2) was investigated as chiral auxiliary for asymmetric NCA nucleophilic synthesis of 6-[{sup 18}F]Fluoro-L-DOPA. Direct condensation of 3,4-dimethoxy-2-[{sup 18}F]fluorobenzaldehyde (1a) or 6-[{sup 18}F]fluoro-piperonal (1b) in the presence of NaH with 2 gave the corresponding [{sup 18}F]-3-[(2-fluorophenyl)methylene]-3,5,6,7,8,8a-hexahydro-7,7,8 a-trimethyl-[6S-(3Z,3{alpha},6{alpha},8{alpha},8{alpha}{beta})]-6, 8-methano-2H-1,4-benzoxazin-2-one derivative 3a or 3b as a single stereoisomer. L-Selectride promoted hydrogenation of the olefinic double bond of these derivatives, in presence of tertbutyl alcohol, afforded the corresponding [{sup 18}F]-3-[(2-fluorophenyl) methyl]-3,5,6,7,8,8a-hexahydro-7,7,8a-trimethyl-[3S-(3{alpha}, 6{alpha}, 8{alpha}8{alpha}{beta})]-6,8-methano-2H-1,4-benzoxazin-2-one derivatives (4a,b) without affecting the orientation of diasterofacial discrimination. Deprotection of the derivatives 4a,b yielded 6-[{sup 18}F]fluoro-L-DOPA (e.e. >90%, 3% radiochemical yield (EOB), total synthesis time 125 min, specific activity >2000 mCi/{mu}mol). Direct deprotection/reduction of the compounds 3a,b provides the enantiomeric mixture of 6-[{sup 18}F]fluoro-D,L-DOPA (10-12% radiochemical yield) and, after chiral separation, 6-[{sup 18}F]fluoro-L-DOPA (e.e. 98%, 4-5% radiochemical yield). (author).

  13. Synthesis of quinoxaline derivatives via condensation of aryl-1,2-diamines with 1,2-diketones using (NH4)6 Mo7 O24 . 4 H2 O as an efficient, mild and reusable catalyst

    International Nuclear Information System (INIS)

    Hasaninejad, A.; Zare, A.; Mohammadizadeh, M. R.; Karami, Z.

    2009-01-01

    Ammonium heptamolybdate tetrahydrate [(NH 4 ) 6 Mo 7 O 24. 4H 2 O] efficiently catalyzes the condensation of aryl-1,2-diamines with l,2-diketones in EtOH/H 2 O as a green media at room temperature to afford quinoxaline derivatives as biologically interesting compounds. Ease of recycling of the catalyst is one of the most advantages of the proposed method

  14. Crystal structure of (1S,3R,8R,9R,10S-2,4,6-tris(2,2-dichloro-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodec-9-ylcyclotriboroxane

    Directory of Open Access Journals (Sweden)

    Ahmed Benharref

    2015-08-01

    Full Text Available The title compound, C48H75B3Cl6O3, was synthesized in two steps from β-himachalene (3,5,5,9-tetramethyl-2,4a,5,6,7,8-hexahydro-1H-benzocycloheptene, which was isolated from the essential oil of the Atlas cedar (Cedrus Atlantica. The molecule consists of an almost planar cyclotriboroxane ring [maximum deviation = 0.036 (2 Å] linked to three identical fused ring systems with different conformations. Each of the three attached ring systems is built up from a seven-membered ring to which a six- and a three-membered ring are fused. The three six-membered rings have a twist-boat conformation, whereas the seven-membered rings display boat, chair and twist-boat conformations. The dihedral angles between the central boroxane ring and the mean planes of the attached six-membered rings are 63.67 (18, 54.89 (2 and 56.57 (19°. The crystal packing is governed only by van der Waals interactions.

  15. Thermal expansion studies of ThW2O8 and UWO6

    International Nuclear Information System (INIS)

    Keskar, Meera; Krishnan, K.; Sali, S.K.

    2014-01-01

    Thorium and uranium oxysalts with hexavalent cations of elements of VI th group of the periodic table are important from mineralogical, environmental and technological points of view. Several molybdates and tungstates of uranium and thorium are known to have similar structural and thermo-physical properties. Earlier, thermal expansion behavior of ThMo 2 O 8 and UMoO 6 were reported from our laboratory. In the present work, thermal expansion behavior of ThW 2 O 8 and UWO 6 studied under vacuum from ambient to 1000 and 800℃, respectively using high temperature X-ray diffraction (HTXRD) technique is reported

  16. High-quality single crystal growth and magnetic property of Mn4Ta2O9

    Science.gov (United States)

    Cao, Yiming; Xu, Kun; Yang, Ya; Yang, Wangfan; Zhang, Yuanlei; Kang, Yanru; He, Xijia; Zheng, Anmin; Liu, Mian; Wei, Shengxian; Li, Zhe; Cao, Shixun

    2018-06-01

    A large-size single crystal of Mn4Ta2O9 with ∼3.5 mm in diameter and ∼65 mm in length was successfully grown for the first time by a newly designed one-step method based on the optical floating zone technique. Both the clear Laue spots and sharp XRD Bragg reflections suggest the high quality of the single crystal. In Mn4Ta2O9 single crystal, an antiferromagnetic phase transition was observed below Néel temperature 102 K along c axis, which is similar to the isostructural compound Mn4Nb2O9, but differs from the isostructural Co4Nb2O9. Relative dielectric constant at 30 kOe suggests that no magnetoelectric coupling exists in Mn4Ta2O9.

  17. Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H{sub 2}O){sub 2}SO{sub 4} and Cu(tn)Cl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Baranová, Lucia [Civil Engineering Faculty, Department of Applied Mathematics, Technical University of Košice, Vysokoškolská 4 SK-042 00, Košice (Slovakia); Orendáčová, Alžbeta, E-mail: alzbeta.orendacova@upjs.sk [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Čižmár, Erik [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Tarasenko, Róbert; Tkáč, Vladimír [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia); Charles University, Faculty of Mathematics and Physics, Ke Karlovu 5 12116, Prague (Czech Republic); Orendáč, Martin; Feher, Alexander [Center of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9 SK-041 54, Košice (Slovakia)

    2016-04-15

    Organo-metallic compounds Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (en=C{sub 2}H{sub 8}N{sub 2}) and Cu(tn)Cl{sub 2} (tn=C{sub 3}H{sub 10}N{sub 2}) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k{sub B}≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H{sub 2}O){sub 2}SO{sub 4} at T{sub C}=0.9 K while hidden in Cu(tn)Cl{sub 2}. A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H{sub 2}O){sub 2}SO{sub 4} (1) and Cu(tn)Cl{sub 2} (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.

  18. Study of the reversible water vapour sorption process of MgSO{sub 4}.7H{sub 2}O and MgCl{sub 2}.6H{sub 2}O under the conditions of seasonal solar heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Ferchaud, C.J.; De Boer, R. [Eindhoven University of Technology, Department of Mechanical Engineering, Eindhoven (Netherlands); Zondag, H.A.; Veldhuis, J.B.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2012-08-15

    The characterization of the structural, compositional and thermodynamic properties of MgSO{sub 4}.7H{sub 2}O and MgCl{sub 2}.6H{sub O} has been done for seasonal heat storage using in-situ X-ray Diffraction and thermal analyses (TG/DSC) under practical conditions for seasonal heat storage (T{sub max} = 150C, p(H{sub 2}O)=13 mbar). This study showed that these two materials release heat after a dehydration/hydration cycle with energy densities of 0.38 GJ/m{sup 3} for MgSO{sub 4}.7H{sub 2}O and 0.71 GJ/m{sup 3} MgCl{sub 2}.6H{sub 2}O. The low heat release found for MgSO{sub 4}.7H2O is mainly attributed to the amorphization of the material during the dehydration performed at 13 mbar which reduces its sorption capacity during the rehydration. MgCl{sub 2}.6H{sub 2}O presents a high energy density which makes this material interesting for the seasonal heat storage in domestic applications. This material would be able to fulfil the winter heat demand of a passive house estimated at 6 GJ with a packed bed reactor of 8.5 m{sup 3}. However, a seasonal heat storage system based on the water vapour sorption process in MgCl{sub 2}.6H{sub 2}O should be carefully set with a restricted temperature of 40C for the hydration reaction to avoid the liquefaction of the material at ambient temperature which limits its performances for long term storage.

  19. Swift adsorptive removal of Congo red from aqueous solution by K1.33Mn8O16 nanowires.

    Science.gov (United States)

    Wu, Junshu; Li, Hongyi; Wang, Jinshu; Li, Zhifei

    2013-08-01

    A swift and efficient approach to converting organic dye effluents into fresh water could be of substantial benefit. In this study, we presented facile hydrothermal synthesis of K1.33Mn8O16 nanowires in ammonium fluoride (NH4F) aqueous solution. The crystallization process of K1.33Mn8O16 nanowires was investigated. The as-obtained K1.33Mn8O16 nanowires were used for swift adsorptive removal of Congo red from aqueous solution without adjusting pH value at room temperature. Adsorption kinetic experimental data are well described by pseudo-second-order rate kinetic model, and the adsorption isotherm fits Langmuir isotherm model. The present investigation provides an efficient approach to designing and fabricating manganese-based nanomaterials for environmental remediation.

  20. Enhanced electrochemical properties of F-doped Li2MnSiO4/C for lithium ion batteries

    Science.gov (United States)

    Wang, Chao; Xu, Youlong; Sun, Xiaofei; Zhang, Baofeng; Chen, Yanjun; He, Shengnan

    2018-02-01

    The Li2MnSiO4 as a novel cathode material for lithium ion batteries, performs high specific capacity, high thermal stability, low cost and etc. However, it suffers from relatively low electronic conductivity and lithium ion diffusion rate. Herein, we successfully introduce fluorine to Li2MnSiO4 (Li2MnSiO4-xFx, x = 0.00, 0.01, 0.03 and 0.05) to overcome these obstacles. The results show that F doping not only enlarges the lattice parameters but also decreases the particle size, synergistically improving the lithium ion diffusion of Li2MnSiO4. Moreover, F doping increase electronic conductivity of Li2MnSiO4/C by inhibiting the formation of C-O bonds in the carbon layers. Meanwhile, F doping improves the crystallinity and stabilizes the crystal structure of Li2MnSiO4. Finally, the Li2MnSiO3.97F0.03/C with the best electrochemical performances delivers the initial specific discharge capacity of 279 mA h g-1 at 25mA g-1 current density from 1.5 V to 4.8 V. Also, it maintains a higher capacity (201 mA h g-1) than F-free Li2MnSiO4 (145 mA h g-1) after 50 cycles.

  1. MWCNT-MnFe2O4 nanocomposite for efficient hyperthermia applications

    Science.gov (United States)

    Seal, Papori; Hazarika, Monalisa; Paul, Nibedita; Borah, J. P.

    2018-04-01

    In this work we present synthesis of multi-walled carbon nanotube (MWCNT)-Manganese ferrite (MnFe2O4) nanocomposite and its probable application in hyperthermia. MnFe2O4 nanoparticles were synthesized by co-precipitation method. X ray diffractogram (XRD) confirms the formation of cubic phase of MnFe2O4 with preferred crystallographic orientation along (311) plane. High resolution electron microscope (HRTEM) image of the composites confirms the presence of MnFe2O4 spherical nanoparticles on the surface of CNT which are bound strongly to the surface. MWCNT-MnFe2O4 nanocomposite were prepared after acid functionalization of MWCNT. Vibrational features of the synthesized samples were confirmed through Fourier transformed infra-red spectroscopy (FTIR). FTIR spectra of acid functionalized MWCNT shows a peak positioned at ˜1620cm-1 which corresponds to C=O functional group of carboxylic acid. Prepared MnFe2O4 nanoparticles and MWCNT-MnFe2O4 nanocomposites were subjected to hyperthermia studies.

  2. Electronic structures and properties of the rhenium alkoxy derivatives Re2O3(OMe)6, Re4O6(OMe)12, and ReMoO2(OMe)7

    International Nuclear Information System (INIS)

    Ermakov, A.I.; Belousov, V.V.; Drobot, D.V.; Shcheglov, P.A.

    2006-01-01

    The geometrical structures, charge distributions, dipole moments, frequencies of normal vibrations, NMR spectra, and total energies of the chemical bonds for the rhenium alkoxy derivatives Re 2 O 3 (OMe) 6 , Re 4 O 6 (OMe) 12 , and ReMoO 2 (OMe) 7 were calculated by the DFT-B3LYP and Hartree-Fock ab initio methods based on the effective core potential theory (LANL2DZ approximation) and the semiempirical PM3(tm) method. Two optimized structures of Re 2 O 3 (OMe) 6 with close energies were found to substantially differ in geometry, 1 H, 13 C, and 17 O NMR spectra, and dipole moment. Various characteristics of the electronic structures and the trans-effect of the ligands in the compounds under consideration were discussed [ru

  3. Long afterglow properties of Eu2+/Mn2+ doped Zn2GeO4

    International Nuclear Information System (INIS)

    Wan, Minhua; Wang, Yinhai; Wang, Xiansheng; Zhao, Hui; Li, Hailing; Wang, Cheng

    2014-01-01

    Zn 2 GeO 4 :Eu 2+ 0.01 and Zn 2 GeO 4 :Mn 2+ 0.01 long afterglow phosphors were synthesized via a high temperature solid state reaction. X-ray diffraction (XRD), afterglow spectra, decay curves and thermoluminescence curves were utilized to characterize the samples. The X-ray diffraction phases indicate that the doping of small amount of transition metal ions or rare earth ions has no significant influence on the crystal structure of Zn 2 GeO 4 . According to the afterglow spectra, we found that the Zn 2 GeO 4 :Eu 2+ 0.01 exhibits a broad band emission with a peak at 474 nm, which could be ascribed to Eu 2+ transition between 4f 6 5d 1 and 4f 7 electron configurations. The Zn 2 GeO 4 :Mn 2+ 0.01 shows a narrow band emission peaking at 532 nm corresponding to the characteristic transition of Mn 2+ ( 4 T 1 → 6 A 1 ). The thermoluminescence (TL) curves above room temperature are employed for the discussion of the origin of the traps and the mechanism of the persistent luminescence. The results indicate that Zn 2 GeO 4 may be an excellent host material for the rare earth ions or transition metal ions long afterglows. -- Highlights: • Zn 2 GeO 4 :Eu 2+ 0.01 and Zn 2 GeO 4 :Mn 2+ 0.01 long afterglow phosphors were synthesized. • Found that these phosphors possess a persistent luminescence property. • The long afterglow spectra were measured. • Found that these phosphors possess a trap level by thermoluminescence

  4. SiO{sub 2} effect on spectral and colorimetric properties of europium doped SrO{sub 2}-MgO-xSiO{sub 2} (0.8 {<=} x {<=} 1.6) phosphor for white LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Chen, B J; Jang, K W; Lee, H S; Jayasimhadri, M; Cho, E J [Department of Physics, Changwon National University, Changwon, 641-773 (Korea, Republic of); Yi, S S [Department of Photonics, Silla University, Pusan 617-736 (Korea, Republic of); Jeong, J H [Department of Physics, Pukyong National University, Pusan 608-737 (Korea, Republic of)], E-mail: kwjang@changwon.ac.kr

    2009-05-21

    Silicate phosphors with compositions 1.99 SrO{sub 2}-1.0 MgO-xSiO{sub 2}-0.01 Eu{sub 2}O{sub 3} (x = 0.8, 1.0, 1.2, 1.4 and 1.6) were prepared in a reducing atmosphere via a solid state reaction. The resultant phosphors were examined by using x-ray diffraction and confirmed to be a mixture of monoclinic Sr{sub 2}SiO{sub 4} and orthorhombic Mg{sub 2}(Si{sub 2}O{sub 4}). The scanning electron microscope images revealed that SiO{sub 2} content does not influence the morphology of the resultant phosphors. It was also observed that the excitation spectra are dependent on the monitored emission wavelength, and the emission spectra are dependent on the excitation wavelength and the SiO{sub 2} content. The energy transfer between Eu{sup 2+} ions occupying different Sr{sup 2+} sites was discussed. The colour coordinates for these phosphors are tunable based on both the excitation wavelength and the SiO{sub 2} content.

  5. Stress relaxation of La1/2Sr1/2MnO3 and La2/3Ca1/3MnO3 at solid oxide fuel cell interfaces

    International Nuclear Information System (INIS)

    Lussier, A.; Dvorak, J.; Stadler, S.; Holroyd, J.; Liberati, M.; Arenholz, E.; Ogale, S.B.; Wu, T.; Venkatesan, T.; Idzerda, Y.U.

    2008-01-01

    Interfacial stress is thought to have significant effects on electrical and oxygen transport properties in thin films of importance in solid oxide fuel cell applications. We investigate how in-plane biaxial stress modifies the electronic structure of La 2/3 Ca 1/3 MnO 3 and La 1/2 Sr 1/2 MnO 3 thin films prepared by pulsed laser deposition on three different substrates to vary the in-plane stress from tensile to compressive. The electronic structure was probed by X-ray absorption spectroscopy of the Mn L 2,3 -edge to characterize the interfacial disruption in this region in an element-specific, site-specific manner. The compressive or tensile interfacial strain modifies the relative concentrations of La and Sr in the interfacial region in order to achieve a better lattice match to the contact material. This atomic migration generates an interfacial region dominated by a compound with a single valency for the transition metal ion, resulting in a severe barrier to oxygen and electron transport through this region

  6. (2-Methyl-4-oxo-4H-pyran-3-olato-κ2O3,O4bis(triphenylphosphane-κPcopper(I–triphenylphosphane–methanol (1/1/1

    Directory of Open Access Journals (Sweden)

    Fabian M. A. Muller

    2011-05-01

    Full Text Available In the title compound, [Cu(C6H5O3(C18H15P2]·C18H15P·CH3OH, the pyran-4-one ring is appromimately planar (r.m.s deviation = 0.0138 Å, with the CuI atom 0.451 (5 Å out of the plane. The CuI atom has a distorted tetrahedral coordination. The O—Cu—O angle is 80.07 (8° and the P—Cu—P angle is 123.49 (3°. The crystal packing is stablized by intramolecular C—H...O interactions and intermolecular C—H...O and O—H...O interactions.

  7. Disordered crystal structure of 20H-AlON, Al10O3N8

    International Nuclear Information System (INIS)

    Banno, Hiroki; Funahashi, Shiro; Asaka, Toru; Hirosaki, Naoto; Fukuda, Koichiro

    2015-01-01

    The disordered crystal structure of 20H-AlON (Al 10 O 3 N 8 ) was determined by combined use of X-ray powder diffraction and transmission electron microscopy. The title compound is hexagonal with space group P6 3 /mmc (Z=2) and the unit-cell dimensions are a=0.307082(5) nm, c=5.29447(8) nm and V=0.432376(12) nm 3 . The structural model showed the positional disordering of three of the six Al sites in the unit cell. The reliability indices calculated from the Rietveld method were R wp =6.97%, S (=R wp /R e )=1.68, R p =5.45%, R B =5.13% and R F =4.56%. We interpreted the disordered structure of 20H-AlON as a statistical average of six different types of ordered structural configurations, which are composed of an octahedral [Al(O, N) 6 ] layer and tetrahedral [Al(O, N) 4 ] layers. We demonstrated the high correlations between the hexagonal unit-cell dimensions and the octahedral layer concentrations for AlON and SiAlON polytypoids. - Graphical abstract: Variations of a and c/(n O +n T ) with n O /(n O +n T ). The a and c are the hexagonal unit-cell dimensions of AlON, SiAlON and AlN. The n O and n T are, respectively, the numbers of octahedral and tetrahedral layers in the unit cells. The unit-cell dimensions in literature are plotted in black plus for AlON and black cross for SiAlON. The unit-cell dimensions of AlN are a=0.3110 nm and c=0.4980 nm. - Highlights: • Crystal structure of Al10O3N8 is determined by laboratory X-ray powder diffraction. • The atom arrangements are represented by the split-atom model. • Six types of ordered atom arrangements are derived from the disordered structure. • Hexagonal unit-cell dimensions changed systematically for AlON and SiAlON compounds

  8. (3-Methylbenzonitrile-1κN-cis-tetrakis(μ-N-phenylacetamidato-1:2κ4N:O;1:2κ4O:N-dirhodium(II(Rh—Rh

    Directory of Open Access Journals (Sweden)

    Cassandra T. Eagle

    2014-08-01

    Full Text Available The complex molecule of the title compound, [Rh2{N(C6H5COCH3}4(NCC7H7], has crystallographically-imposed mirror symmetry. The four acetamide ligands bridging the dirhodium core are arranged in a 2,2-cis manner with two N atoms and two O atoms coordinating to the unique RhII atom cis to one another. The Neq—Rh—Rh—Oeq torsion angles on the acetamide bridge are 0.75 (7 and 1.99 (9°. The axial nitrile ligand completes the distorted octahedral coordination sphere of one RhII atom and shows a nonlinear coordination, with an Rh—N—C bond angle of 162.8 (5°; the N—C bond length is 1.154 (7 Å.

  9. [Disulfanediylbis(ferrocenylthiophosphinato-κ2O,O]titanocene tetrahydrofuran trisolvate

    Directory of Open Access Journals (Sweden)

    Mehmet Karakus

    2012-04-01

    Full Text Available The title compound, [Fe2Ti(C5H54(C10H8O2P2S4]·3C4H8O, contains a central seven-membered TiO2P2S2 ring with a very similar geometry compared to the derivative showing anisyl instead of ferrocenyl substituents, the Ti—O distance being marginally longer for the anisyl derivative. Two tetrahydrofuran solvent molecules are each disordered on a twofold axis.

  10. Poly[[tetraaqua(μ3-naphthalene-1,6-disulfonato-κ4O1:O6,O6′:O6′′strontium(II] monohydrate

    Directory of Open Access Journals (Sweden)

    Shan Gao

    2011-12-01

    Full Text Available In the crystal structure of the polymeric title compound, {[Sr(C10H6O6S2(H2O4]·H2O}n, the naphthalene-1,6-disulfonate dianion uses one –SO3 unit to O,O′-chelate to an SrII cation and its third O atom to bind to another SrII cation. The other –SO3 unit binds to yet another SrII atom. The four coordinated water molecules are monodentate but one is disordered over two positions in a 1:1 ratio. The μ3-bonding mode of the dianion generates a polymeric three-dimensional network; the network is consolidated by O—H...O hydrogen bonds. The SrII cation exists in an undefined eight-coordinate environment.

  11. Investigations on the crystal-structure and non-ambient behaviour of K2Ca2Si8O19 - a new potassium calcium silicate

    Science.gov (United States)

    Schmidmair, Daniela; Kahlenberg, Volker; Praxmarer, Alessandra; Perfler, Lukas; Mair, Philipp

    2017-09-01

    Within the context of a systematic re-investigation of phase relationships between compounds of the ternary system K2O-CaO-SiO2 a new potassium calcium silicate with the chemical formula K2Ca2Si8O19 was synthesized via solid state reactions as well as the flux method using KCl as a solvent. Its crystal structure was determined from single-crystal X-ray diffraction data by applying direct methods. The new compound crystallizes in the triclinic space group P 1 bar . Unit cell dimensions are a = 7.4231(7) Å, b = 10.7649(10) Å, c = 12.1252(10) Å, α = 70.193(8)°, β = 83.914(7)° and γ = 88.683(7)°. K2Ca2Si8O19 is built up of corner-connected, slightly distorted [SiO4]-tetrahedra forming double-sheets, which are linked by double-chains of edge-sharing [CaO6]-octahedra. Electroneutrality of the material is provided by additional potassium atoms that are located within the voids of the silicate layers and between adjacent [Ca2O6]-double-chains. Further characterization of the compound was performed by Raman spectroscopy and differential thermal analysis. The behaviour of K2Ca2Si8O19 under high-temperature and high-pressure was investigated by in-situ high-temperature powder X-ray diffraction up to a maximum temperature of 1125 °C and a piston cylinder experiment at 1.5 GPa and 1100 °C. Additionally an overview of known double-layer silicates is given as well as a comparison of K2Ca2Si8O19 to closely related structures.

  12. Coating effect of LiFePO4 and Al2O3 on Li1.2Mn0.54Ni0.13Co0.13O2 cathode surface for lithium ion batteries

    CSIR Research Space (South Africa)

    Seteni, Bonani

    2017-06-01

    Full Text Available Lithium-manganese-rich cathode material Li1.2Mn0.54Ni0.13Co0.13O2 is prepared by combustion method, and then coated with nano-sized LiFePO4 and nano-sized Al2O3 particles via a wet chemical process. The as-prepared Li1.2Mn0.54Ni0.13Co0.13O2, LiFePO4...

  13. Lithium-Excess Research of Cathode Material Li2MnTiO4 for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Xinyi Zhang

    2015-11-01

    Full Text Available Lithium-excess and nano-sized Li2+xMn1−x/2TiO4 (x = 0, 0.2, 0.4 cathode materials were synthesized via a sol-gel method. The X-ray diffraction (XRD experiments indicate that the obtained main phases of Li2.0MnTiO4 and the lithium-excess materials are monoclinic and cubic, respectively. The scanning electron microscope (SEM images show that the as-prepared particles are well distributed and the primary particles have an average size of about 20–30 nm. The further electrochemical tests reveal that the charge-discharge performance of the material improves remarkably with the lithium content increasing. Particularly, the first discharging capacity at the current of 30 mA g−1 increases from 112.2 mAh g−1 of Li2.0MnTiO4 to 187.5 mAh g−1 of Li2.4Mn0.8TiO4. In addition, the ex situ XRD experiments indicate that the monoclinic Li2MnTiO4 tends to transform to an amorphous state with the extraction of lithium ions, while the cubic Li2MnTiO4 phase shows better structural reversibility and stability.

  14. (La, Pr)0.8Sr0.2FeO3-δ-Sm 0.2Ce0.8O2-δ composite cathode for proton-conducting solid oxide fuel cells

    KAUST Repository

    Chen, Yonghong

    2014-08-01

    Mixed rare-earth (La, Pr)0.8Sr0.2FeO 3-δ-Sm0.2Ce0.8O2-δ (LPSF-SDC) composite cathode was investigated for proton-conducting solid oxide fuel cells based on protonic BaZr0.1Ce0.7Y 0.2O3-δ (BZCY) electrolyte. The powders of La 0.8-xPrxSr0.2FeO3-δ (x = 0, 0.2, 0.4, 0.6), Sm0.2Ce0.8O2-δ (SDC) and BaZr0.1Ce0.7Y0.2O3-δ (BZCY) were synthesized by a citric acid-nitrates self-propagating combustion method. The XRD results indicate that La0.8-xPrxSr 0.2FeO3-δ samples calcined at 950 °C exhibit perovskite structure and there are no interactions between LPSF0.2 and SDC at 1100 °C. The average thermal expansion coefficient (TEC) of LPSF0.2-SDC, BZCY and NiO-BZCY is 12.50 × 10-6 K-1, 13.51 × 10-6 K-1 and 13.47 × 10-6 K -1, respectively, which can provide good thermal compatibility between electrodes and electrolyte. An anode-supported single cell of NiO-BZCY|BZCY|LPSF0.2-SDC was successfully fabricated and operated from 700 °C to 550 °C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. A high maximum power density of 488 mW cm -2, an open-circuit potential of 0.95 V, and a low electrode polarization resistance of 0.071 Ω cm2 were achieved at 700 °C. Preliminary results demonstrate that LPSF0.2-SDC composite is a promising cathode material for proton-conducting solid oxide fuel cells. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  15. Nd2(SeO3)2(SeO4) . 2H2O - a mixed-valence compound containing selenium in the oxidation states +IV and +VI

    International Nuclear Information System (INIS)

    Berdonosov, P.S.; Dityat'yev, O.A.; Dolgikh, V.A.; Schmidt, P.; Ruck, Michael; Lightfoot, P.

    2004-01-01

    Pale pink crystals of Nd 2 (SeO 3 ) 2 (SeO 4 ) . 2H 2 O were synthesized under hydrothermal conditions from H 2 SeO 3 and Nd 2 O 3 at about 200 C. X-ray diffraction on powder and single-crystals revealed that the compound crystallizes with the monoclinic space group C 2/c (a = 12.276(1) A, b = 7.0783(5) A, c = 13.329(1) A, β = 104.276(7) ). The crystal structure of Nd 2 (SeO 3 ) 2 (SeO 4 ) . 2H 2 O is an ordered variant of the corresponding erbium compound. Eight oxygen atoms coordinate the Nd III atom in the shape of a bi-capped trigonal prism. The oxygen atoms are part of pyramidal (Se IV O 3 ) 2- groups, (Se VI O 4 ) 2- tetrahedra and water molecules. The [NdO 8 ] polyhedra share edges to form chains oriented along [010]. The selenate ions link these chains into layers parallel to (001). The layers are interconnected by the selenite ions into a three-dimensional framework. The dehydration of Nd 2 (SeO 3 ) 2 (SeO 4 ) . 2H 2 O starts at 260 C. The thermal decomposition into Nd 2 SeO 5 , SeO 2 and O 2 at 680 C is followed by further loss of SeO 2 leaving cubic Nd 2 O 3 . (Abstract Copyright [2004], Wiley Periodicals, Inc.) [de

  16. Bulk modulus of basic sodalite, Na8[AlSiO4]6(OH)2·2H2O, a possible zeolitic precursor in coal-fly-ash-based geopolymers

    KAUST Repository

    Oh, Jae Eun; Moon, Juhyuk; Mancio, Mauricio; Clark, Simon M.; Monteiro, Paulo J.M.

    2011-01-01

    Synthetic basic sodalite, Na8[AlSiO4] 6(OH)22H2O, cubic, P43n, (also known as hydroxysodalite hydrate) was prepared by the alkaline activation of amorphous aluminosilicate glass, obtained from the phase separation of Class F fly ash. The sample

  17. KMoWP3O12, a tunnel structure of the KMo2O12-type

    International Nuclear Information System (INIS)

    Benmoussa, A.; Leclaire, A.; Grandin, A.; Raveau, B.

    1989-01-01

    Potassium molybdotungstotriphosphate(V), KMoWP 3 O 12 , M r =603.80, orthorhombic, Pbcm, a=8.8180(6), b=9.1574(8), c=12.3836(8) A, V=1000.0(2) A 3 , Z=4, D x =4.01 Mg m -3 , λ(Mo Kα)=0.71073 A, μ=13.9 mm -1 , T=294 K, F(000)=276, R=0.035 and wR=0.042 for 2291 observed reflections. The framework is built up from MoO 6 octahedra and PO 4 tetrahedra which delimit tunnels running along b, where the K ions are located. The structure leads to the formula KMoWO(PO 4 )(P 2 O 7 ). (orig.)

  18. Low-temperature heat capacities and thermodynamic properties of ethylenediammonium tetrachlorozincate chloride (C2H10N2)2(ZnCl4)Cl2

    International Nuclear Information System (INIS)

    He, Dong-Hua; Di, You-Ying; Wang, Bin; Dan, Wen-Yan; Tan, Zhi-Cheng

    2010-01-01

    The ethylenediammonium tetrachlorozincate chloride (C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 was synthesized. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the complex. Low-temperature heat capacities of the compound were measured by a precision automatic adiabatic calorimeter over the temperature range from T = 77-377 K. A polynomial equation of heat capacities as a function of the reduced temperature was fitted by a least square method. Based on the polynomial equation, the smoothed heat capacities and thermodynamic functions of the title compound relative to the standard reference temperature 298.15 K were calculated at intervals of 5 K. A thermochemical cycle was designed and the enthalpy change of the solid phase reaction of ethylenediamine dihydrochloride with zinc chloride was determined to be Δ r H m o =-(17.9±0.6)kJmol -1 by an isoperibol solution-reaction calorimeter. Finally, the standard molar enthalpy of formation of the title compound was derived to be Δ f H m o [(C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 ,s]=-(1514.4±2.7)kJmol -1 in accordance with Hess law.

  19. Three Cyanide-Bridged One-Dimensional Single Chain Co"I"I"I-Mn"I"I Complexes: Rational Design, Synthesis, Crystal Structures and Magnetic Properties

    International Nuclear Information System (INIS)

    Zhang, Daopeng; Zhao, Zengdian; Wang, Ping; Chen, Xia

    2012-01-01

    Two pyridinecarboxamide dicyanidecobalt(III) building blocks and two mononuclear seven-coordinated macrocycle manganese(II) compounds have been rationally selected to assemble cyanide-bridged heterobimetallic complexes, resulting in three cyanide-bridged Co"I"I"I-Mn"I"I complexes. Single X-ray diffraction analysis show that these complexes {[Mn(L"1)][Co(bpb)]}ClO_4·CH_3OH·0.5H_2O (1), {[Mn(L"2)][Co(bpb)]}ClO_4·0.5CH_3OH (2) and {[Mn(L"1)][Cobpmb]}ClO_4·H_2O (3) (L"1 = 3,6-diazaoctane-1,8-diamine, L"2 = 3,6-dioxaoctano-1,8- diamine: bpb"2"- = 1,2-bis(pyridine-2-carboxamido)benzenate, bpmb"2"- = 1,2-bis(pyridine-2-carboxamido)-4- methyl-benzenate) all present predictable one-dimensional single chain structures. The molecular structures of these one-dimensional complexes consists of alternating units of [Mn(L)]"2"+ (L = L"1 or L"2) and [Co(L')(CN)_2]"- (L' = bpb"2"-, or bpmb"2"-), forming a cyanide-bridged cationic polymeric chain with free ClO_4"- as the balance anion. The coordination geometry of manganese(II) ion in the three one-dimensional complexes is a slightly distorted pentagonal-bipyrimidal with two cyanide nitrogen atoms at the trans positions and N_5 or N_3O_2 coordinating mode at the equatorial plane from ligand L"1 or L"2. Investigation over magnetic properties of these complexes reveals that the very weak magnetic coupling between neighboring Mn(II) ions connected by the diamagnetic dicyanidecobalt(III) building block. A best-fit to the magnetic susceptibility of complex 1 leads to the magnetic coupling constants J = .0.084(3) cm"-"1

  20. Assembly of a new inorganic-organic frameworks based on [Sb4Mo12(OH)6O48]10- polyanion

    Science.gov (United States)

    Thabet, Safa; Ayed, Meriem; Ayed, Brahim; Haddad, Amor

    2014-10-01

    A new organic-inorganic hybrid material, (C4N2H7)8[K(H2O)]2[Sb4Mo12(OH)6O48]ṡ16H2O (1) has been isolated by the conventional solution method and characterized by elemental analysis, single-crystal X-ray diffraction, infrared spectroscopy, UV-visible spectroscopies, cyclic voltammetry and TG-DTA analysis. The compound crystallizes in the triclinic space group P - 1 with a = 13.407(6) Å, b = 13.906(2) Å, c = 14.657(7) Å, α = 77.216(9)°, β = 71.284(6)°, γ = 71.312(3)° and Z = 1. The crystal structure exhibits an infinite 1D inorganic structure built from [Sb4Mo12(OH)6O48]10- clusters and potassium cations; adjacent chains are further joined up hydrogen bonding interactions between protonated 2-methylimidazolim cations, water molecules and polyoxoanions to form a 3D supramolecular architecture.

  1. Immunochemical characterization of the O antigens of two Proteus strains, O8-related antigen of Proteus mirabilis 12 B-r and O2-related antigen of Proteus genomospecies 5/6 12 B-k, infecting a hospitalized patient in Poland.

    Science.gov (United States)

    Drzewiecka, Dominika; Shashkov, Alexander S; Arbatsky, Nikolay P; Knirel, Yuriy A

    2016-05-01

    A hospitalized 73-year-old woman was infected with a Proteus mirabilis strain, 12 B-r, isolated from the place of injection of a blood catheter. Another strain, 12 B-k, recognized as Proteus genomospecies 5 or 6, was isolated from the patient's faeces, which was an example of a nosocomial infection rather than an auto-infection. Serological investigation using ELISA and Western blotting showed that strain 12 B-k from faeces belonged to the Proteus O2 serogroup. Strain 12 B-r from the wound displayed cross-reactions with several Proteus O serogroups due to common epitopes on the core or O-specific parts of the lipopolysaccharide. Studies of the isolated 12 B-r O-specific polysaccharide by NMR spectroscopy revealed its close structural similarity to that of Proteus O8. The only difference in 12 B-r was the presence of an additional GlcNAc-linked phosphoethanolamine residue, which creates a putative epitope responsible for the cross-reactivity with Pt. mirabilis O16. The new O-antigen form could appear as a result of adaptation of the bacterium to a changing environment. On the basis of the data obtained, we suggest division of the O8 serogroup into two subgroups: O8a for strains of various Proteus species that have been previously classified into the O8 serogroup, and O8a,b for Pt. mirabilis 12 B-r, where 'a' is a common epitope and 'b' is a phosphoethanolamine-associated epitope. These findings further confirm serological and structural heterogeneity of O antigens of Proteus strains isolated lately from patients in Poland.

  2. New silicate-germanate Cs2Pb2[(Si0.6Ge0.4)2O7] from the series A2Pb2[B2O7], A = K, Cs, B = Si, Ge with the umbrella-like [PbO3]4- group

    Science.gov (United States)

    Belokoneva, Elena L.; Morozov, Ivan A.; Volkov, Anatoly S.; Dimitrova, Olga V.; Stefanovich, Sergey Yu.

    2018-04-01

    New silicate-germanate Cs2Pb2[(Si0.6Ge0.4)2O7] was synthesized in multi-components hydrothermal solution with 20 w.% concentration of Cs2CO3 mineralizer, pH = 10. Novel mixed compound belongs to the structure type A2Pb2[B2O7] previously indicated for powders with A = K, B=Si or Ge. Singe crystal structure determination of Cs2Pb2[(Si0.6Ge0.4)2O7] revealed the need for the correction of the space group of the earlier suggested structural model from P-3 to P-3m1, as well as for the splitting of the Pb-atom position. Umbrella-like groups [PbO3]4- are located between [(Si,Ge)O4]4- tetrahedra in mica-like honeycomb layers and play the role of tetrahedra with the Pb-lone-pair as the forth apex. Crystal chemical comparison revealed similarities and differences with the classical structure type of α-celsian Ba[Al2Si2O8] with the tetrahedral double layer. Recently investigated nonlinear optical acentric borates Pb2(BO3)(NO3) and Pb2(BO3)Cl are both related to this structural type, possessing umbrella-like groups [PbO3]4- and honeycomb layers [Pb2(BO3)]+ with the BO3-triangles on the tetrahedral positions.

  3. Synthesis of poly(3,4-propylenedioxythiophene/MnO2 composites and their applications in the adsorptive removal of methylene blue

    Directory of Open Access Journals (Sweden)

    Ruxangul Jamal

    2016-02-01

    Full Text Available The poly(3,4-propylenedioxythiophene/MnO2 composites (PProDOT/MnO2 were prepared successfully by soaking the PProDOT powders into potassium permanganate (KMnO4 solution, with the mass ratio of PProDOT and KMnO4 from 2:1 to 1:2. The structure and morphology of composites were characterized by Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, ultraviolet–visible absorption spectra (UV, X-ray diffraction (XRD, energy-dispersive X-ray spectroscopy (EDX and field emission scanning electron microscope (FE-SEM. Furthermore, PProDOT/MnO2 composites were tested as the adsorbents for removal of methylene blue (MB from aqueous solution. The results revealed that the composites were successfully synthesized, and the thiophene sulfur was oxidized into sulfoxide by KMnO4. The highest percentage removal of MB after 30 min was 91% for PProDOT/MnO2 (1:2 composite, and the percentage removal of MB was ~12 mg g−1 after 60 min at initial concentrations of MB dye of 5.6 mg L−1 in the case of PProDOT/MnO2 (1:2 composite. Besides, the adsorption process of PProDOT/MnO2 (1:2 composite was described by pseudo-second-order and Langmuir models.

  4. Crystal structure and spectroscopic behavior of synthetic novgorodovaite Ca2(C2O4)Cl2·2H2O and its twinned triclinic heptahydrate analog

    Science.gov (United States)

    Piro, Oscar E.; Echeverría, Gustavo A.; González-Baró, Ana C.; Baran, Enrique J.

    2018-02-01

    Synthetic novgorodovaite analog Ca2(C2O4)Cl2·2H2O is identical to its natural counterpart. It crystallizes in the monoclinic I2/ m space group with a = 6.9352(3), b = 7.3800(4), c = 7.4426(3) Å, β = 94.303(4)°, V = 379.85(3) Å3 and Z = 2. The heptahydrate analog, Ca2(C2O4)Cl2·7H2O, crystallizes as triclinic twins in the P \\overline{1} space group with a = 7.3928(8), b = 8.9925(4), c = 10.484(2) Å, α = 84.070(7), β = 70.95(1), γ = 88.545(7)°, V = 655.3(1) Å3 and Z = 2. The crystal packing of both calcium oxalate-chloride double salts favors the directional bonding of oxalate, C2O4 2-, ligands to calcium ions as do other related calcium oxalate minerals. The π-bonding between C and O atoms of the C2O4 2- oxalate group leaves sp 2-hydridised orbitals of the oxygen atoms available for bonding to Ca. Thus, the Ca-O bonds in both calcium oxalate-chloride double salts are directed so as to lie in the plane of the oxalate group. This behavior is reinforced by the short O···O distances between the oxygens attached to a given carbon atom, which favors them bonding to a shared Ca atom in bidentate fashion. Strong bonding in the plane of the oxalate anion and wide spacing perpendicular to that plane due to repulsion between oxalate π-electron clouds gives rise to a polymerized structural units which are common to both hydrates, explaining the nearly equal cell constants 7.4 Å which are defined by the periodicity of Ca-oxalate chains in the framework (monoclinic b ≈ triclinic a). When compared with novgorodovaite, the higher water content of Ca2(C2O4)Cl2·7H2O leads to some major differences in their structures and ensuing physical properties. While novgorodovaite has a three-dimensional framework structure, in the higher hydrate, the highly polar water molecules displace chloride ions from the calcium coordination sphere and surround them through OwH···Cl hydrogen bonds. As a result, polymerization in Ca2(C2O4)Cl2·7H2O solid is limited to the formation

  5. Phase formation in the systems ZrO2-H2SO4-Na2SO4 (NaCl)-H2O

    International Nuclear Information System (INIS)

    Sozinova, Yu.P.; Motov, D.L.; Rys'kina, M.P.

    1988-01-01

    Formation of solid phases in the systems ZrO 2 - H 2 SO 4 - Na 2 SO 4 (NaCl) - H 2 O at 25 and 75 deg C is studied. Three basic Na 2 Zr(OH) 2 (SO 4 ) 2 x (0.2 - 0.4)H 2 O, NaZrOH(SO 4 ) 2 x H 2 O, NaZrO 0.5 (OH) 2 SO 4 x 2H 2 O and three normal sodium sulfatozirconates Na 2 Zr(SO 4 ) 3 x 3H 2 O, Na 4 Zr(SO 4 ) 4 x 3H 2 O, Na 6 Zr(SO 4 ) 5 x 4H 2 O have been isolated, their solubility and crystal optical properties are determined

  6. XMCD study of the Ruddlesden-Popper phase La1.2Nd0.2Sr1.6Mn2O7

    International Nuclear Information System (INIS)

    Weigand, F.; Goering, E.; Geissler, J.; Justen, M.; Ruck, K.; Schuetz, G.; Doerr, K.

    2001-01-01

    X-ray Magnetic Circular Dichroism (XMCD) measurements of the Ruddlesden-Popper Phase La 1.2 Nd 0.2 Sr 1.6 Mn 2 O 7 are reported. The Mn K, La and Nd L 2 , 3 edges have been measured on a powder sample at two different magnetic fields at low temperature. The analysis of the spectra at B = 1T indicates a large orbital moment of the Nd 5d-states and a significant spin-polarization of the La 5d-band. Furthermore at the Mn Κ-edge a XMCD-signal is observed, showing a polarization of the Mn 4p-band. At lower field (0.2T) all XMCD-signals are about two times smaller corresponding to the lower total magnetization. The signal at the Nd L 2 edge vanishes completely at 0.2T. (au)

  7. Non-enzymatic detection of glucose in fruits using TiO2-Mn3O4 hybrid nano interface

    Science.gov (United States)

    Jayanth Babu, K.; Sasya, Madhurantakam; Nesakumar, Noel; Shankar, Prabakaran; Gumpu, Manju Bhargavi; Ramachandra, Bhat Lakshmishri; Kulandaisamy, Arockia Jayalatha; Rayappan, John Bosco Balaguru

    2017-08-01

    Consumption of fruits leads to increase in glucose level in blood for diabetic patients, which in turn leads to peripheral, vascular, ocular complications and cardiac diseases. In this context, a non-enzymatic hybrid glucose biosensor was fabricated for the first time to detect glucose by immobilizing titanium oxide-manganese oxide (TiO2-Mn3O4) nanocomposite and chitosan membrane on to the surface of Pt working electrode (Pt/TiO2-Mn3O4/chitosan). TiO2-Mn3O4 nanocomposite catalyzed the oxidation of glucose to gluconolactone in the absence of glucose oxidase enzyme with high electron transfer rate, good biocompatibility and large surface coverage. Electrochemical measurements revealed the excellent sensing response of the developed biosensor towards glucose with a high sensitivity of 7.073 µA mM-1, linearity of 0.01-0.1 mM, low detection limit of 0.01 µM, reproducibility of 1.5% and stability of 98.8%. The electrochemical parameters estimated from the anodic process were subjected to linear regression models for the detection of unknown concentration of glucose in different fruit samples.

  8. Poly[[diaquabis(2,2′-bipyridine-κ2N,N′(μ3-5-hydroxyisophthalato-κ5O1,O1′:O3,O3′:O3′(μ3-5-hydroxyisophthalato-κ4O1,O1′:O3:O3′(μ2-5-hydroxyisophthalato-κ3O1,O1′:O3didysprosium(III] dihydrate

    Directory of Open Access Journals (Sweden)

    Yan-Lin Zhang

    2011-10-01

    Full Text Available The polymeric title compound, {[Dy2(C8H4O53(C10H8N22(H2O22H2O}n, contains two independent DyIII ions, both of which are nine-coordinated in a distorted tricapped trigonal–prismatic geometry. One DyIII ion is coordinated by five 5-hydroxyisophthalate (hip ligands and one 2,2′-bipyridine (bpy ligand and the other by three hip ligands, one bpy ligand and two water molecules. The DyIII ions are bridged by the carboxylate groups of the hip ligands, forming a three-dimensional framework. O—H...O hydrogen bonds are present in the crystal structure.

  9. New Insights into Mn1−xZnxFe2O4 via Fabricating Magnetic Photocatalyst Material BiVO4/Mn1−xZnxFe2O4

    Directory of Open Access Journals (Sweden)

    Taiping Xie

    2018-02-01

    Full Text Available BiVO4/Mn1−xZnxFe2O4 was prepared by the impregnation roasting method. XRD (X-ray Diffractometer tests showed that the prepared BiVO4 is monoclinic crystal, and the introduction of Mn1−xZnxFe2O4 does not change the crystal structure of BiVO4. The introduction of a soft-magnetic material, Mn1−xZnxFe2O4, was beneficial to the composite photocatalyst’s separation from the liquid solution using an extra magnet after use. UV-vis spectra analysis indicated that Mn1−xZnxFe2O4 enhanced the absorption intensity of visible light for BiVO4. EIS (electrochemical impedance spectroscopy investigation revealed that the introduction of Mn1−xZnxFe2O4 enhanced the conductivity of BiVO4, further decreasing its electron transfer impedance. The photocatalytic efficiency of BiVO4/Mn1−xZnxFe2O4 was higher than that of pure BiVO4. In other words, Mn1−xZnxFe2O4 could enhance the photocatalytic reaction rate.

  10. Cs_7Sm_1_1[TeO_3]_1_2Cl_1_6 and Rb_7Nd_1_1[TeO_3]_1_2Br_1_6, the new tellurite halides of the tetragonal Rb_6LiNd_1_1[SeO_3]_1_2Cl_1_6 structure type

    International Nuclear Information System (INIS)

    Charkin, Dmitri O.; Black, Cameron; Downie, Lewis J.; Sklovsky, Dmitry E.; Berdonosov, Peter S.; Olenev, Andrei V.; Zhou, Wuzong; Lightfoot, Philip; Dolgikh, Valery A.

    2015-01-01

    Two new rare-earth – alkali – tellurium oxide halides were synthesized by a salt flux technique and characterized by single-crystal X-ray diffraction. The structures of the new compounds Cs_7Sm_1_1[TeO_3]_1_2Cl_1_6 (I) and Rb_7Nd_1_1[TeO_3]_1_2Br_1_6 (II) (both tetragonal, space group I4/mcm) correspond to the sequence of [MLn_1_1(TeO_3)_1_2] and [M_6X_1_6] layers and bear very strong similarities to those of known selenite analogs. We discuss the trends in similarities and differences in compositions and structural details between the Se and Te compounds; more members of the family are predicted. - Graphical abstract: Two new rare-earth – alkali – tellurium oxide halides were predicted and synthesized. - Highlights: • Two new rare-earth – alkali – tellurium oxide halides were synthesized. • They adopt slab structure of rare earth-tellurium-oxygen and CsCl-like slabs. • The Br-based CsCl-like slabs have been observed first in this layered family.

  11. Methyl 4′,5-dichloro-2-hydroxy-4,6-dimethylbiphenyl-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Muhammad Adeel

    2012-04-01

    Full Text Available In the title compound, C16H14Cl2O3, the dihedral angle between the mean planes of the two benzene rings is 55.30 (5°. The methyl ester group lies within the ring plane due to an intramolecular O—H...O hydrogen bond [maximum deviation from the C8O2 mean plane is 0.0383 (13 Å]. In the crystal, molecules are held together by rather weak C—H...O hydrogen bonds.

  12. Bis(2-methoxybenzylammonium diaquabis(dihydrogen diphosphato-κ2O,O′cobaltate(II dihydrate

    Directory of Open Access Journals (Sweden)

    Adel Elboulali

    2014-04-01

    Full Text Available The title compound, (C8H12NO2[Co(H2P2O72(H2O22H2O, crystallizes isotypically with its MnII analogue. It consists of alternating layers of organic cations and inorganic complex anions, extending parallel to (100. The complex cobaltate(II anion exhibits -1 symmetry. Its Co2+ atom has an octahedral coordination sphere, defined by two water molecules in apical positions and two H2P2O72− ligands in equatorial positions. The cohesion between inorganic and organic layers is accomplished by a set of O—H...O and N—H...O hydrogen bonds involving the organic cation, the inorganic anion and the remaining lattice water molecules.

  13. Synthesis and crystal structure of the cesium silver permanganate Cs_3Ag[MnO_4]_4

    International Nuclear Information System (INIS)

    Bauchert, Joerg M.; Henning, Harald; Schleid, Thomas

    2012-01-01

    After successful syntheses and structural refinements of the already known permanganates of cesium (Cs[MnO_4]) and silver (Ag[MnO_4]) we started to blend aqueous solutions of both components in various molar ratios. From crystallization experiments of these mixtures only three species of crystals with different chemical compositions were obtained: tricesium monosilver tetrakispermanganate (Cs_3Ag[MnO_4]_4) and, depending upon the respective ratio, either additional silver permanganate or surplus cesium permanganate, namely. The new title compound crystallizes in the orthorhombic space group Pnnm (no. 58) with two formula units per unit cell and cell dimensions of a = 764.53(4), b = 1883.57(9) and c = 584.34(3) pm. The crystal structure of Cs_3Ag[MnO_4]_4 consists of two crystallographically distinguishable cesium cations. (Cs1)"+ is surrounded by fourteen oxygen atoms constructing a slightly distorted bicapped hexagonal prism. These polyhedra are connected through edge-sharing with two other polyhedra of this kind to form chains along [001]. The chains are linked to each other via sixfold coordinated Ag"+ cations (d(Ag-O) = 238-246 pm), arranged in such a manner that they link three oxygen atoms of two cesium polyhedra, leading to a two-dimensional layer spreading out parallel to the (001) plane. Together with the two crystallographically different tetrahedral oxomanganate(VII) anions [MnO_4]"- (d(Mn-O) = 161-162 pm) the other kind of cesium cations ((Cs2)"+ with CN = 13) finally connect these layers three-dimensionally. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Post mortem analysis of fatigue mechanisms in LiNi0.8Co0.15Al0.05O2 - LiNi0.5Co0.2Mn0.3O2 - LiMn2O4/graphite lithium ion batteries

    Science.gov (United States)

    Lang, Michael; Darma, Mariyam Susana Dewi; Kleiner, Karin; Riekehr, Lars; Mereacre, Liuda; Ávila Pérez, Marta; Liebau, Verena; Ehrenberg, Helmut

    2016-09-01

    The fatigue of commercial lithium ion batteries after long-term cycling at two different temperatures and cycling rates is investigated. The cells are opened after cycling and post-mortem analysis are conducted. Two main contributions to the capacity loss of the batteries are revealed. The loss of active lithium leads to a relative shift between anodes and cathodes potentials. A growth of the solid electrolyte interface (SEI) on the anode is determined as well as the formation of lithium fluoride species as an electrolyte decomposition product. Those effects are reinforced by increasing cycling rates from 1C/2C (charge/discharge) to 2C/3C as well as by increasing cycling temperatures from 25 °C to 40 °C. The other contribution to the capacity loss originates from a fatigue of the blended cathodes consisting of LiNi0.5Co0.2Mn0.3O2 (NCM), LiNi0.8Co0.15Al0.05O2 (NCA) and LiMn2O4 (LMO). Phase-specific capacity losses and fatigue mechanisms are identified. The layered oxides tend to form microcracks and reveal changes of the surface structure leading to a worsening of the lithium kinetics. The cathode exhibits a loss of manganese at 40 °C cycling temperature. Cycling at 40 °C instead of 25 °C has the major impact on cathodes capacity loss, while cycling at 2C/3C rates barely influences it.

  15. Synthesis and electrochemical characterization of nano-CeO2-coated nanostructure LiMn2O4 cathode materials for rechargeable lithium batteries

    International Nuclear Information System (INIS)

    Arumugam, D.; Kalaignan, G. Paruthimal

    2010-01-01

    LiMn 2 O 4 spinel cathode materials were coated with 0.5, 1.0, and 1.5 wt.% CeO 2 by a polymeric process, followed by calcination at 850 o C for 6 h in air. The surface-coated LiMn 2 O 4 cathode materials were physically characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron microscopy (XPS). XRD patterns of CeO 2 -coated LiMn 2 O 4 revealed that the coating did not affect the crystal structure or the Fd3m space group of the cathode materials compared to uncoated LiMn 2 O 4 . The surface morphology and particle agglomeration were investigated using SEM, TEM image showed a compact coating layer on the surface of the core materials that had average thickness of about 20 nm. The XPS data illustrated that the CeO 2 completely coated the surface of the LiMn 2 O 4 core cathode materials. The galvanostatic charge and discharge of the uncoated and CeO 2 -coated LiMn 2 O 4 cathode materials were measured in the potential range of 3.0-4.5 V (0.5 C rate) at 30 o C and 60 o C. Among them, the 1.0 wt.% of CeO 2 -coated spinel LiMn 2 O 4 cathode satisfies the structural stability, high reversible capacity and excellent electrochemical performances of rechargeable lithium batteries.

  16. Apparent and standard molar volumes and heat capacities of aqueous Ni(ClO4)2 from 25 to 85oC

    International Nuclear Information System (INIS)

    Pan, P.; Campbell, A.B.

    1997-01-01

    Apparent molar heat capacities and volumes of aqueous Ni(ClO 4 ) 2 were measured from 25 to 85 o C over a concentration range of 0.02 to 0.8 mol-kg -1 using a Picker flow microcalorimeter and a Picker vibrating-tube densimeter. An extended Debye-Huckel equation was fitted to the experimental data to obtain expressions for the apparent molar properties as functions of ionic strength for Ni(ClO 4 ) 2 (aq). The standard-state partial molar properties for Ni(ClO 4 ) 2 (aq) in the temperature range 25 to 85 o C were obtained and can be expressed by empirical equations. The standard partial molar heat capacities and volumes for Ni 2+ (aq) from 25 to 86 o C were obtained by using the additivity rule and data for ClO - 4 (aq) in the literature. These values were extrapolated to 300 o C by employing the Helgeson-Kirkham-Flower (HKF) equations, amended to include a standard-state correction term. (author)

  17. Synthesis of ceramic powders of La{sub 9,56} (SiO{sub 4}){sub 6}O{sub 2,34} and La{sub 9,8}Si{sub 5,7}Mg{sub O,3}O{sub 26,}4 by modified sol-gel process; Sintese de pos ceramicos de La{sub 9,56} (SiO{sub 4}){sub 6}O{sub 2,34} e La{sub 9,8}Si{sub 5,7}Mg{sub O,3}O{sub 26,}4 por processo sol-gel modificado

    Energy Technology Data Exchange (ETDEWEB)

    Lira, Sabrina Lopes; Paiva, Mayara Rafaela Soares; Misso, Agatha Matos; Elias, Daniel Ricco; Yamagata, Chieko, E-mail: yamagata@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

    2012-07-01

    Lanthanum silicate oxyapatite materials are promising for application as electrolyte in solid oxide fuel cells because of high ionic conductivity at temperatures between 600 deg C and 800 deg C. In this work, oxyapatites with the composition La{sub 9,56}(SiO{sub 4}){sub 6}O{sub 2,34}, and La{sub 9,8}Si{sub 5,7}Mg{sub 0,3}O{sub 26,4} were synthesized by using the sol-gel method, followed by precipitation. Initially, the gel of silica was synthesized from sodium silicate solution, by acid catalysis using lanthanum and magnesium chloride solution. Then, the La and Mg hydroxides were precipitated with NaOH in the gel. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and measurements of specific surface area. The crystalline oxyapatite phase of La{sub 9,56}(SiO{sub 4}){sub 6}O{sub 2,34}, and was La{sub 9,8}Si{sub 5,7}Mg{sub 0,3}O{sub 26,4} obtained by calcination at 900 deg C for 2 and 1h respectively (author)

  18. High mobility half-metallicity in the (LaMnO3)2/(SrTiO3)8 superlattice

    KAUST Repository

    Cossu, Fabrizio

    2013-01-28

    First principles calculations have been performed to investigate the LaMnO3/SrTiO3 superlattice. Structural relaxation within the generalized gradient approximation results in no significant tiltings or rotations of oxygen octahedra, but in distinct distortions in the SrTiO3 region. Taking into account the onsite Coulomb interaction, we find that the Mn spins order ferromagnetically, in contrast to the antiferromagnetic state of bulk LaMnO3. Most importantly, the interface strain combined with charge transfer across the interface induces half-metallicity within the MnO2 layers. The superlattice is particulary interesting for spintronics applications because the half-metallic states are characterized by an extraordinary high mobility.

  19. High mobility half-metallicity in the (LaMnO3)2/(SrTiO3)8 superlattice

    KAUST Repository

    Cossu, Fabrizio; Schwingenschlö gl, Udo; Singh, Nirpendra

    2013-01-01

    First principles calculations have been performed to investigate the LaMnO3/SrTiO3 superlattice. Structural relaxation within the generalized gradient approximation results in no significant tiltings or rotations of oxygen octahedra, but in distinct distortions in the SrTiO3 region. Taking into account the onsite Coulomb interaction, we find that the Mn spins order ferromagnetically, in contrast to the antiferromagnetic state of bulk LaMnO3. Most importantly, the interface strain combined with charge transfer across the interface induces half-metallicity within the MnO2 layers. The superlattice is particulary interesting for spintronics applications because the half-metallic states are characterized by an extraordinary high mobility.

  20. Two anhydrous zeolite X crystal structures, Pd sub 1 sub 8 Tl sub 5 sub 6 Si sub 1 sub 0 sub 0 Al sub 9 sub 2 O sub 3 sub 8 sub 4 and Pd sub 2 sub 1 Tl sub 5 sub 0 Si sub 1 sub 0 sub 0 Al sub 9 sub 2 O sub 3 sub 8 sub 4

    CERN Document Server

    Yoon, B Y; Lee, S H; Kim, Y

    2001-01-01

    The crystal structures of fully dehydrated Pd sup 2 sup + - and Tl sup + -exchanged zeolite X, Pd sub 1 sub 8 Tl sub 5 sub 6 Si sub 1 sub 0 sub 0 Al sub 9 sub 2 O sub 3 sub 8 sub 4 (Pd sub 1 sub 8 Tl sub 5 sub 6 X, a = 24.935(4) A) and Pd sub 2 sub 1 Tl sub 5 sub 0 Si sub 1 sub 0 sub 0 Al sub 9 sub 2 O sub 3 sub 8 sub 4 (Pd sub 2 sub 1 Tl sub 5 sub 0 -X, a = 24.914(4) A), have been determined by single-crystal X-ray diffraction methods in the cubic space group Fd3 at 21(1) .deg. C. The crystals were prepared using an exchange solution that had a Pd(NH sub 3) sub 4 Cl sub 2 : TINO sub 3 mole ratio of 50 : 1 and 200 : 1, respectively, with a total concentration of 0.05 M for 4 days. After dehydration at 360 .deg. C and 2 x 10 sup - sup 6 Torr in flowing oxygen for 2 days, the crystals were evacuated at 21(1) .deg. C for 2 hours. They were refined to the final error indices R sub 1 = 0.045 and R sub 2 = 0.038 with 344 reflections for Pd sub 1 sub 8 Tl sub 5 sub 6 -X, and R sub 1 = 0.043 and R sub 2 = 0.045 with ...

  1. Synthesis and characterization of new fluoride-containing manganese vanadates A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} (A=Rb, Cs) and Mn{sub 2}VO{sub 4}F

    Energy Technology Data Exchange (ETDEWEB)

    Sanjeewa, Liurukara D. [Department of Chemistry and Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson, SC 29634-0973 (United States); McGuire, Michael A. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Smith Pellizzeri, Tiffany M.; McMillen, Colin D. [Department of Chemistry and Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson, SC 29634-0973 (United States); Ovidiu Garlea, V. [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Willett, Daniel; Chumanov, George [Department of Chemistry and Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson, SC 29634-0973 (United States); Kolis, Joseph W., E-mail: kjoseph@clemson.edu [Department of Chemistry and Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson, SC 29634-0973 (United States)

    2016-09-15

    Large single crystals of A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} (A=Rb, Cs) and Mn{sub 2}VO{sub 4}F were grown using a high-temperature (~600 °C) hydrothermal technique. Single crystal X-ray diffraction and powder X-ray diffraction were utilized to characterize the structures, which both possess MnO{sub 4}F{sub 2} building blocks. The A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} series crystallizes as a new structure type in space group Pbcn (No. 60), Z=4 (Rb{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2}: a=7.4389(17) Å, b=11.574(3) Å, c=10.914(2) Å; Cs{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2}: a=7.5615(15) Å, b=11.745(2) Å, c=11.127(2) Å). The structure is composed of zigzag chains of edge-sharing MnO{sub 4}F{sub 2} units running along the a-axis, and interconnected through V{sub 2}O{sub 7} pyrovanadate groups. Temperature dependent magnetic susceptibility measurements on this interesting one-dimensional structural feature based on Mn{sup 2+} indicated that Cs{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} is antiferromagnetic with a Neél temperature, T{sub N}=~3 K and a Weiss constant, θ, of −11.7(1) K. Raman and infrared spectra were also analyzed to identify the fundamental V–O vibrational modes in Cs{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2}. Mn{sub 2}(VO{sub 4})F crystalizes in the monoclinic space group of C2/c (no. 15), Z=8 with unit cell parameters of a=13.559(2) Å, b=6.8036(7) Å, c=10.1408(13) Å and β=116.16(3)°. The structure is associated with those of triplite and wagnerite. Dynamic fluorine disorder gives rise to complex alternating chains of five-and six-coordinate Mn{sup 2+}. These interpenetrating chains are additionally connected through isolated VO{sub 4} tetrahedra to form the condensed structure. - Graphical abstract: New vanadate fluorides A{sub 2}Mn{sub 2}V{sub 2}O{sub 7}F{sub 2} (A=Rb, Cs) and Mn{sub 2}(VO{sub 4})F have been synthesized hydrothermally. Upon cooling, the one-dimensional Mn(II) substructure results in antiferromagnetic

  2. Synthesis, surface group modification of 3D MnV2O6 nanostructures and adsorption effect on Rhodamine B

    International Nuclear Information System (INIS)

    Zhang, Wanqun; Shi, Lei; Tang, Kaibin; Liu, Zhongping

    2012-01-01

    Highlights: ► Fabrication of urchin-like MnV 2 O 6 with oxygen-containing surface groups. ► Mn 0.5 V 2 O 5 ·nH 2 O as an intermediate product holds the key to the final products. ► 3D architectures of MnV 2 O 6 with oxygen-containing surface groups as sorbent. ► The sorbent shows a good adsorption ability. -- Abstract: Highly uniform 3D MnV 2 O 6 nanostructures modified by oxygen functional groups (-COO-) were successfully prepared in large quantities by an approach involving preparation of vanadyl ethylene glycolate as the precursor. The growth and self-assembly of MnV 2 O 6 nanobelts and nanorods could be readily tuned by additive species and quantities, which brought different morphologies and sizes to the final products. With a focus on the regulation of structure, the formation process of 3D architectures of MnV 2 O 6 by self-assembly of nanobelts was followed by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD). The consecutive processes of vanadyl ethylene glycolate and benzoyl peroxide assisted formation of layered structure Mn 0.5 V 2 O 5 ·nH 2 O, growth of aligned MnV 2 O 6 nanobelts, and oriented assembly were proposed for the growth mechanism. The band gap vs. different morphology was also studied. Optical characterization of these MnV 2 O 6 with different morphologies showed direct bandgap energies at 1.8–1.95 eV. The adsorption properties of 3D MnV 2 O 6 nanostructures synthesized under different conditions were investigated through the removal test of Rhodamine B in aqueous water, and the 3D nanostructures synthesized with 30 g L −1 benzoyl peroxide showed good adsorption capability of Rhodamine B.

  3. Frustrated pyrochlore oxides, Y2Mn2O7, Ho2Mn2O7, and Yb2Mn2O7: Bulk magnetism and magnetic microstructure

    DEFF Research Database (Denmark)

    Greedan, J.E.; Raju, N.P.; Maignan, A.

    1996-01-01

    The bulk magnetic properties, including de and ac susceptibilities and heat capacity, of the pyrochlore oxides Ho2Mn2O7 and Yb2Mn2O7 are reported and compared with those of the previously studied Y2Mn2O7. In the latter case the magnetic Mn4+ ions occupy the 16c sites in Fd3m which define...... for all three materials are reported for the Q range 10(-2) Angstrom(-1) to 2x10(-1) Angstrom(-1) and the temperature range 6-100 K. Data for the full Q range can be fitted for all three materials to a model consisting of a Lorentzian and a Lorentzian-squared term, i.e., I(Q)=A/(Q(2)+1/xi(1)(2))+B/(Q(2......)+1/xi(2)(2))(2), a cross section commonly found in spin-glass-like materials. A surprising result is that the correlation lengths xi(1) and xi(2) are unequal and in general xi(2)>xi(1). xi(1) remains finite reaching maximum values which range from 10 to 20 Angstrom depending on the compound, while xi(2...

  4. Influence of bismuth on the magnetic and electrical properties of La2MnNiO6 .IAEA.ATOMS

    International Nuclear Information System (INIS)

    Nautiyal, Pranjal; Motin Seikh, Md.; Pralong, V.; Kundu, Asish K.

    2013-01-01

    In this study, we report the ambient pressure and low temperature synthesis of ordered perovskite La 2−x Bi x Mn 1+y Ni 1−y O 6 with high bismuth content. Keeping y=0, we are able to substitute La by Bi up to x=0.4 i.e. 20% of La. However, 50% La could be replaced by Bi for y=0.5 without any impurity phases. Interestingly, these compounds remain ferromagnetic with the Curie temperature T C of 255 and 75 K for La 1.6 Bi 0.4 MnNiO 6 and LaBiMn 1.5 Ni 0.5 O 6 compositions, respectively. Moreover, these Bi-substituted phases become more conducting, three order of magnitude higher, at room temperature compared to the parent La 2 MnNiO 6 phase. - Highlights: • Synthesis of bismuth based perovskite at ambient pressure and low temperature with 50% Bi-doped phase. • Magnetic interactions between Mn and Ni ions have been proposed clearly for the doped phases • The band gap energy in the samples have been determined to explain their higher conductivity

  5. Construction of Six Coordination Polymers Based on a 5,5′-(1,2-Ethynyl)bis-1,3-benzenedicarboxylic Ligand: Synthesis, Structure, Gas Sorption, and Magnetic Properties

    KAUST Repository

    Zheng, Bing

    2013-03-06

    Six novel coordination polymers based on a multifunctional ligand, 5,5\\'-(1,2-ethynyl)bis-1,3-benzenedicarboxylic (H4EBDC), namely, |(C3H7NO)2(H2O)7(C 2H5OH)3| [Zn2(C18H 6O8)(C10H8N2) 2] (1), |(C3H7NO)3(H2O)30- (CH3CN)2|[Zn 6(C18H6O8)3(C 6H12N2O2)2] (2), |(C 3H7NO)2- (H2O)2(H 3O)2|[Cd3(C18H6O 8)2] (3), |(C3H7NO)|[Mn- (C 18H8O8)(C3H7NO) 2] (4), |(C3H7NO)2(H2O)(C 2H7N)3| [Mn6(C18H 7O8)4(H2O)8] (5), and [Mn2(C18H6O8)(C3H 7NO)2] (6), have been constructed under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction. In these compounds, the ligand, H4EBDC, exhibits different coordination modes and conformations, constructing various architectures by bridging a variety of metal ions or polynuclear clusters. Compound 1 forms a three-dimensional (3D) FSC network constructed from two-dimensional (2D) layer motifs joined by EBDC4- and 4,4\\'-bipyridine bridges. Compound 2 possesses an NbO topology by linking Zn2(CO2)4 units with the ligand, coordinated amine molecules fill the pores, while compound 3 exhibits a 3D FLU network with Cd2+ as the cation and features an infinite framework built from tricadmium clusters. Compound 4 is based on PtS net, constructed of 4-connected rectangular H4EBDC units with tetrahedral monometallic Mn(CO2)4 nodes. Compound 5 is composed of 2D layers with (3,6)-connected KGD topology, and compound 6 consists of a 3D PtS-X network, built by bridging a metal chain with the ligand. The structures of these compounds have been discussed together with their corresponding properties, such as gas storage, separation, and magnetic properties. © 2013 American Chemical Society.

  6. μ-Oxalato-κ4O1,O2:O1′,O2′-bis[aqua(2,2′-bipyridine-κN(nitrato-κ2O,O′lead(II

    Directory of Open Access Journals (Sweden)

    Gang-Hong Pan

    2012-10-01

    Full Text Available The title compound, [Pb2(C2O4(NO32(C10H8N22(H2O2], was synthesized hydrothermally. The binuclear complex molecule is centrosymmetric, the inversion centre being located at the mid-point of the oxalate C—C bond. The PbII ion is heptacoordinated by the O atom of one water molecule, two oxalate O atoms, two nitrate O atoms and two 2,2′-bipyridine N atoms, forming an irregular coordination environemnt. Intermolecular O—H...O hydrogen bonds between water molecules and oxalate and nitrate ions result in the formation of layers parallel to (010. π–π interactions between pyridine rings in adjacent layers, with centroid–centroid distances of 3.584 (2 Å, stabilize the structural set-up.

  7. Synthesis and crystal structure of Bi6.4Pb0.6P2O15.2

    International Nuclear Information System (INIS)

    Arumugam, N.; Lynch, V.; Steinfink, H.

    2007-01-01

    Bi 6.4 Pb 0.6 P 2 O 15.2 is a polymorph of structures with the general stoichiometry Bi 6+x M 1-x P 2 O 15+y . However, unlike previously published structures that consist of layers formed by edge sharing OBi 4 tetrahedra bridged by PO 4 and TO 6 (T=transition metal) tetrahedra and octahedra the title compound's structure is more complex. It is monoclinic, C2, a=19.4698(4) A, b=11.3692(3) A, c=16.3809(5) A, β=101.167(1) o , Z=10. Single-crystal X-ray diffraction data were refined by least squares on F 2 converging to R 1 =0.0387, wR 2 =0.0836 for 7023 intensities. The crystal twins by mirror reflection across (001) as the twin plane and twin component 1 equals 0.74(1). Oxygen ions are in tetrahedral coordination to four metal ions and the O(BiPb) 4 units share corners to form layers that are part of the three-dimensional framework. Eight oxygen ions form a cube around the two crystallographically independent Pb ions. Pb-O bond lengths vary from 2.265(14) to 2.869(14) A. Pairs of such cubes share an edge to form a Pb 3 O 20 unit. The two oxygen ions from the unshared edges are part of irregular Bi polyhedra. Other oxygen ions of Bi polyhedra are part only of O(BiPb) 4 units, and some oxygen ions of the polyhedra are also part of PO 4 tetrahedra. One, two, three and or four PO 4 moieties are connected to the Bi polyhedra. Bi-O bond lengths ≤3.1 A vary from 2.090(12) to 3.07(3) A. The articulations of Pb cubes, Bi polyhedra and PO 4 tetrahedra link into the three-dimensional structure. - Graphical abstract: View of the structure of Bi 6.4 Pb 0.6 P 2 O 15.2 parallel to the b-axis

  8. {6,6′-Dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne]diphenolato-1κ4O1,O1′,O6,O6′:2κ4O1,N,N′,O1′}(ethanol-1κO-μ-nitrato-1:2κ2O:O′-dinitrato-1κ4O,O′-samarium(IIIzinc(II

    Directory of Open Access Journals (Sweden)

    Qiang Huang

    2009-10-01

    Full Text Available In the title heteronuclear ZnII–SmIII complex, [SmZn(C18H18N2O4(NO33(CH3CH2OH], with the hexadentate Schiff base compartmental ligand N,N′-bis(3-methoxysalicylideneethylenediamine (H2L, the SmIII and ZnII ions are triply bridged by two phenolate O atoms from the Schiff base ligand and one nitrate anion. The five-coordinate ZnII ion is in a square-pyramidal geometry formed by the donor centers of two imine N atoms, two phenolate O atoms and one of the bridging nitrate O atoms. The SmIII center is in a ten-fold coordination of O atoms, involving the phenolate O atoms, two methoxy O atoms, one ethanol O atom, and two O atoms from two nitrate anions and one from the bridging nitrate anion. In the crystal, intermolecular O—H...O and C—H...O interactions generate a layer structure extending parallel to (101.

  9. Low-temperature resistivity anomaly in underdoped Pr0.8Sr0.2MnO3 manganite nanoparticles

    International Nuclear Information System (INIS)

    Das, Proloy T.; Giri, S.K.; Panda, J.; Taraphder, A.; Nath, T.K.; Nigam, A.K.

    2013-01-01

    High resolution electrical resistivity measurements were carried out of under-doped Pr 0.8 Sr 0.2 MnO 3 manganite nanoparticles with grain size modulation down to 40 nm in magnetic fields H, from 0 to 9 T in the low temperature regime down to a temperature of 4.2 K. In the temperature range below 80 K, a distinct resistivity minima is observed for all the samples with different particle sizes for all H. While trying to fit low temperature resistivity data with different models for the observed resistivity minima with negative temperature coefficient of resistance (TCR) for all H, it appears that all the data for different particle sizes, can be best described by electron-electron (e-e) interaction effect in comparison with other models, e.g., Kondo model, coulomb blockades etc. The low temperature data for all H have been fitted with an expression containing three terms, namely, residual resistivity, inelastic scattering, e-e interaction and Kondo effects. We conclude that the e-e interaction is the dominant transport mechanism at low temperatures for the observed negative TCR in this strongly disordered nanometric Pr 0.8 Sr 0.2 MnO 3 phase separated manganite system. (author)

  10. Three-Dimensional NiCo2O4@MnMoO4 Core-Shell Nanoarrays for High-Performance Asymmetric Supercapacitors.

    Science.gov (United States)

    Yuan, Yuliang; Wang, Weicheng; Yang, Jie; Tang, Haichao; Ye, Zhizhen; Zeng, Yujia; Lu, Jianguo

    2017-10-10

    Design of new materials with sophisticated nanostructure has been proven to be an efficient strategy to improve their properties in many applications. Herein, we demonstrate the successful combination of high electron conductive materials of NiCo 2 O 4 with high capacitance materials of MnMoO 4 by forming a core-shell nanostructure. The NiCo 2 O 4 @MnMoO 4 core-shell nanoarrays (CSNAs) electrode possesses high capacitance of 1169 F g -1 (4.24 F cm -2 ) at a current density of 2.5 mA cm -2 , obviously larger than the pristine NiCo 2 O 4 electrode. The asymmetric supercapacitors (ASCs), assembled with NiCo 2 O 4 @MnMoO 4 CSNAs as binder-free cathode and active carbon (AC) as anode, exhibit high energy density of 15 Wh kg -1 and high power density of 6734 W kg -1 . Cycle performance of NiCo 2 O 4 @MnMoO 4 CSNAs//AC ASCs, conducted at current density of 20 mA cm -2 , remain 96.45% of the initial capacitance after 10,000 cycles, demonstrating its excellent long-term cycle stability. Kinetically decoupled analysis reveals that the capacitive capacitance is dominant in the total capacitance of NiCo 2 O 4 @MnMoO 4 CSNAs electrode, which may be the reason for ultra long cycle stability of ASCs. Our assembled button ASC can easily light up a red LED for 30 min and a green LED for 10 min after being charged for 30 s. The remarkable electrochemical performance of NiCo 2 O 4 @MnMoO 4 CSNAs//AC ASCs is attributed to its enhanced surface area, abundant electroactive sites, facile electrolyte infiltration into the 3D NiCo 2 O 4 @MnMnO 4 nanoarrays and fast electron and ion transport path.

  11. A highly sensitive hydrogen peroxide amperometric sensor based on MnO2-modified vertically aligned multiwalled carbon nanotubes.

    Science.gov (United States)

    Xu, Bin; Ye, Min-Ling; Yu, Yu-Xiang; Zhang, Wei-De

    2010-07-26

    In this report, a highly sensitive amperometric sensor based on MnO(2)-modified vertically aligned multiwalled carbon nanotubes (MnO(2)/VACNTs) for determination of hydrogen peroxide (H(2)O(2)) was fabricated by electrodeposition. The morphology of the nanocomposite was characterized by scanning electron microscopy, energy-dispersive X-ray spectrometer and X-ray diffraction. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy were applied to investigate the electrochemical properties of the MnO(2)/VACNTs nanocomposite electrode. The mechanism for the electrochemical reaction of H(2)O(2) at the MnO(2)/VACNTs nanocomposite electrode was also discussed. In borate buffer (pH 7.8, 0.20 M), the MnO(2)/VACNTs nanocomposite electrode exhibits a linear dependence (R=0.998) on the concentration of H(2)O(2) from 1.2 x 10(-6)M to 1.8 x 10(-3)M, a high sensitivity of 1.08 x 10(6) microA M(-1) cm(-2) and a detection limit of 8.0 x 10(-7) M (signal/noise=3). Meanwhile, the MnO(2)/VACNTs nanocomposite electrode is also highly resistant towards typical inorganic salts and some biomolecules such as acetic acid, citric acid, uric acid and D-(+)-glucose, etc. In addition, the sensor based on the MnO(2)/VACNTs nanocomposite electrode was applied for the determination of trace of H(2)O(2) in milk with high accuracy, demonstrating its potential for practical application. Copyright 2010 Elsevier B.V. All rights reserved.

  12. Synthesis and characterization of the new copper indium phosphate Cu{sub 8}In{sub 8}P{sub 4}O{sub 30}

    Energy Technology Data Exchange (ETDEWEB)

    Hanzelmann, Christian; Weimann, Iren; Feller, Joerg [Hochschule fuer Technik und Wirtschaft Dresden, Friedrich-List-Platz 1, 01069 Dresden (Germany); Zak, Zdirad [Masaryk University, Kotlarska 267/2, 61137 Brno (Czech Republic)

    2014-01-15

    The system CuO/In{sub 2}O{sub 3}/P{sub 2}O{sub 5} has been investigated using solid state reaction between CuO, In{sub 2}O{sub 3} and (NH{sub 4}){sub 2}HPO{sub 4} in silica glass crucibles at 900 C. The powder samples were characterized by X-ray diffraction, thermal analysis and FT-IR spectroscopy. Orange single crystals of the new quaternary phase were achieved by the process of crystallization with mineralizers in sealed silica glass ampoules. They were then analyzed with EDX and single-crystal X-ray analysis in which the composition Cu{sub 8}In{sub 8}P{sub 4}O{sub 30} with the triclinic space group P anti 1 (No 2) with a = 7,2429(14) Aa, b = 8,8002(18) Aa, c = 10,069(2) Aa, α = 103,62(3) , β = 106,31(3) , γ = 101,55(3) and Z = 1 was found. The three-dimensional framework consists of [InO{sub 6}] octahedra and distorted [CuO{sub 6}] octahedra, overcaped [InO{sub 7}] prisms and [PO{sub 4}] tetrahedra, also trigonal [(CuIn)O{sub 5}] bipyramids and distorted [(CuIn)O{sub 6}] octahedra, where copper and indium are partly exchanged against each other. Cu{sub 8}In{sub 8}P{sub 4}O{sub 30} exhibits an incongruent melting point at 1023 C. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. No solid solution compounds in between the binaries. Syntheses and crystal structures of Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and NbI{sub 2}Cl{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Reckeweg, Olaf; Schleid, Thomas [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie

    2018-04-01

    The anion-mixed niobium tetrahalides Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and NbI{sub 2}Cl{sub 2} were obtained by heating NbBr{sub 5} with NbCl{sub 5} and NbI{sub 5} with NbCl{sub 5}, respectively, in equimolar ratios with niobium metal in evacuated, torch-sealed silica ampoules at 720 K for 3 days. The orthorhombic title compounds form as very brittle black needles and were characterized by single-crystal X-ray diffraction [space group: Immm, Z=4; a=704.27(6), b=824.13(7), c=929.64(8) pm for Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and a=753.76(6), b=829.38(7) and c=983.41(8) pm for NbI{sub 2}Cl{sub 2}]. Surprisingly enough, these mixed-anionic halides are not isostructural with either NbCl{sub 4}, NbBr{sub 4} or NbI{sub 4}, but crystallize isotypically with TaI{sub 2}Cl{sub 2}, thus being examples for differential site occupancy stabilized materials. Structural features of other niobium(IV) halides are compiled and compared to those of Nb(Br{sub 0.62(4)}Cl{sub 0.38(4)}){sub 2}Cl{sub 2} and NbI{sub 2}Cl{sub 2}. Except for NbF{sub 4}, they all exhibit chains of trans-edge connected [NbX{sub 6}]{sup 2-} octahedra, which allow Peierls distortions to form Nb-Nb single bonds. The packing of these chains differ, however, depending on the actual halide or mixed-halide combination.

  14. Synthesis, Characterization, and Microwave-Absorbing Properties of Polypyrrole/MnFe2O4 Nanocomposite

    Directory of Open Access Journals (Sweden)

    Seyed Hossein Hosseini

    2012-01-01

    Full Text Available Conductive polypyrrole (PPy-manganese ferrite (MnFe2O4 nanocomposites with core-shell structure were synthesized by in situ polymerization in the presence of dodecyl benzene sulfonic acid (DBSA as the surfactant and dopant and iron chloride (FeCl3 as the oxidant. The structure and magnetic properties of manganese ferrite nanoparticles were measured by using powder X-ray diffraction (XRD and vibrating sample magnetometer (VSM, respectively. Its morphology, microstructure, and DC conductivity of the nanocomposite were characterized by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, and four-wire technique, respectively. The microwave-absorbing properties of the nanocomposite powders dispersing in resin acrylic coating with the coating thickness of 1.5 mm were investigated by using vector network analyzers in the frequency range of 812 GHz. A minimum reflection loss of −12 dB was observed at 11.3 GHz.

  15. Near ultraviolet photodissociation spectroscopy of Mn{sup +}(H{sub 2}O) and Mn{sup +}(D{sub 2}O)

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, Wright L.; Copeland, Christopher; Kocak, Abdulkadir; Sallese, Zachary; Metz, Ricardo B., E-mail: rbmetz@chem.umass.edu [Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003 (United States)

    2014-11-28

    The electronic spectra of Mn{sup +}(H{sub 2}O) and Mn{sup +}(D{sub 2}O) have been measured from 30 000 to 35 000 cm{sup −1} using photodissociation spectroscopy. Transitions are observed from the {sup 7}A{sub 1} ground state in which the Mn{sup +} is in a 3d{sup 5}4s{sup 1} electronic configuration, to the {sup 7}B{sub 2} (3d{sup 5}4p{sub y}) and {sup 7}B{sub 1} (3d{sup 5}4p{sub x}) excited states with T{sub 0} = 30 210 and 32 274 cm{sup −1}, respectively. Each electronic transition has partially resolved rotational and extensive vibrational structure with an extended progression in the metal−ligand stretch at a frequency of ∼450 cm{sup −1}. There are also progressions in the in-plane bend in the {sup 7}B{sub 2} state, due to vibronic coupling, and the out-of-plane bend in the {sup 7}B{sub 1} state, where the calculation illustrates that this state is slightly non-planar. Electronic structure computations at the CCSD(T)/aug-cc-pVTZ and TD-DFT B3LYP/6-311++G(3df,3pd) level are also used to characterize the ground and excited states, respectively. These calculations predict a ground state Mn-O bond length of 2.18 Å. Analysis of the experimentally observed vibrational intensities reveals that this bond length decreases by 0.15 ± 0.015 Å and 0.14 ± 0.01 Å in the excited states. The behavior is accounted for by the less repulsive p{sub x} and p{sub y} orbitals causing the Mn{sup +} to interact more strongly with water in the excited states than the ground state. The result is a decrease in the Mn-O bond length, along with an increase in the H-O-H angle. The spectra have well resolved K rotational structure. Fitting this structure gives spin-rotation constants ε{sub aa}″ = −3 ± 1 cm{sup −1} for the ground state and ε{sub aa}′ = 0.5 ± 0.5 cm{sup −1} and ε{sub aa}′ = −4.2 ± 0.7 cm{sup −1} for the first and second excited states, respectively, and A′ = 12.8 ± 0.7 cm{sup −1} for the first excited state. Vibrationally mediated

  16. Structural, dielectric and magnetic properties of Bi{sub 0.8}Ba{sub 0.2}Fe{sub 0.6}Mn{sub 0.4}O{sub 3} ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Rangi, Manisha, E-mail: mrangi100@gmail.com; Sanghi, S.; Agarwal, A.; Kaswan, K.; Jangra, S.; Singh, O. [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India)

    2016-05-23

    Polycrystalline Bi{sub 0.8}Ba{sub 0.2}Fe{sub 0.6}Mn{sub 0.4}O{sub 3} ceramic was synthesized via conventional two stage solid state reaction method. The crystal structure is examined via powder x-ray diffraction and Rietveld refinement revealed that the sample has a rhombohedral crystal structure (space group R3c). The dielectric response of the sample was analyzed in the frequency range 10 Hz to 5 MHz at different temperature. The values of dielectric constant (ε′) and dielectric loss factor (tan δ) increases with increasing temperature at different frequencies which may be the result of increase in the number of charge carriers and their mobilities due to the thermal activation. M-H hysteresis loop was recorded at room temperature up to a field of 15 kOe which shows that there is slightly enhancement in magnetization with co-doping.

  17. Low-Temperature Sintering Li3Mg1.8Ca0.2NbO6 Microwave Dielectric Ceramics with LMZBS Glass

    Science.gov (United States)

    Wang, Gang; Zhang, Huaiwu; Liu, Cheng; Su, Hua; Jia, Lijun; Li, Jie; Huang, Xin; Gan, Gongwen

    2018-05-01

    Li3Mg1.8Ca0.2NbO6 ceramics doped with Li2O-MgO-ZnO-B2O3-SiO2 glass (LMZBS) were prepared via a solid-state route. The LMZBS glass effectively reduced the sintering temperature of Li3Mg1.8Ca0.2NbO6 ceramics to 950°C. The effects of the LMZBS glass on the sintering behavior, microstructures and microwave dielectric properties of Li3Mg1.8Ca0.2NbO6 ceramics are discussed in detail. Among all the LMZBS doped Li3Mg1.8Ca0.2NbO6 ceramics, the sample with 1 wt.% of LMZBS glass sintered at 950°C for 4 h exhibited good dielectric properties: ɛ r = 16.7, Q × f = 31,000 GHz (9.92 GHz), τ f = - 1.3 ppm/°C. The Li3Mg1.8Ca0.2NbO6 ceramics possessed excellent chemical compatibility with Ag electrodes, and could be applied in low temperature co-fired ceramics (LTCC) applications.

  18. K(MoO24O3(AsO4

    Directory of Open Access Journals (Sweden)

    Raja Jouini

    2013-06-01

    Full Text Available A new compound with a non-centrosymmetric structure, potassium tetrakis[dioxomolybdenum(IV] arsenate trioxide, K(MoO24O3(AsO4, has been synthesized by a solid-state reaction. The [(MoO24O3(AsO4]+ three-dimensional framework consists of single arsenate AsO4 tetrahedra, MoO6 octahedra, MoO5 bipyramids and bioctahedral units of edge-sharing Mo2O10 octahedra. The [Mo2O8]∞ octahedral chains running along the a-axis direction are connected through their corners to the AsO4 tetrahedra, MoO6 octahedra and MoO5 bipyramids, so as to form large tunnels propagating along the a axis in which the K+ cations are located. This structure is compared with compounds containing M2O10 (M = Mo, V, Fe dimers and with those containing M2O8 (M = V chains.

  19. Porous MnCo2O4 as superior anode material over MnCo2O4 nanoparticles for rechargeable lithium ion batteries

    Science.gov (United States)

    Baji, Dona Susan; Jadhav, Harsharaj S.; Nair, Shantikumar V.; Rai, Alok Kumar

    2018-06-01

    Pyro synthesis is a method to coat nanoparticles by uniform layer of carbon without using any conventional carbon source. The resultant carbon coating can be evaporated in the form of CO or CO2 at high temperature with the creation of large number of nanopores on the sample surface. Hence, a porous MnCo2O4 is successfully synthesized here with the same above strategy. It is believed that the electrolyte can easily permeate through these nanopores into the bulk of the sample and allow rapid access of Li+ ions during charge/discharge cycling. In order to compare the superiority of the porous sample synthesized by pyro synthesis method, MnCo2O4 nanoparticles are also synthesized by sol-gel synthesis method at the same parameters. When tested as anode materials for lithium ion battery application, porous MnCo2O4 electrode shows high capacity with long lifespan at all the investigated current rates in comparison to MnCo2O4 nanoparticles electrode.

  20. Syntheses, crystal structures and solid-state properties of the lanthanoid-containing nanoclusters [(Ln{sub 2}PW{sub 10}O{sub 38}){sub 4}(W{sub 3}O{sub 8})(OH){sub 4}(H{sub 2}O){sub 2}]{sup 26-}

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Rakesh; Saini, Mukesh Kumar; Hussain, Firasat [Department of Chemistry, University of Delhi (India)

    2014-12-15

    A series of lanthanoid-substituted polyoxometalates have been synthesized by a self-assembly process in potassium chloride solution by the reaction of dilacunary [P{sub 2}W{sub 19}O{sub 69}(H{sub 2}O)]{sup 14-} with mid- and late-lanthanoid Ln(NO{sub 3}){sub 3}.nH{sub 2}O salts leading to the formation of the tetrameric tungstophosphates [(Ln{sub 2}PW{sub 10}O{sub 38}){sub 4}(W{sub 3}O{sub 8})(OH){sub 4}(H{sub 2}O){sub 2}]{sup 26-} [Ln = Y{sup 3+} (1), Sm{sup 3+} (2), Eu{sup 3+} (3), Gd{sup 3+} (4), Tb{sup 3+} (5), Dy{sup 3+} (6), Ho{sup 3+} (7), Er{sup 3+} (8), Tm{sup 3+} (9), Yb{sup 3+} (10)]. The polyanions were isolated as potassium or mixed-alkali salts. Most of the compounds were characterized by single-crystal X-ray diffraction and various analytical techniques, such as FTIR, UV/Vis, {sup 31}P NMR and photoluminescence spectroscopy, magnetism, as well as thermogravimetric analysis. The FTIR spectra suggest that all the compounds are isomorphous. The crystal structures of these complexes consist of four A-[α-PW{sub 10}O{sub 36}]{sup 7-} units, each incorporating two Ln{sup III} ions to create four Keggin-like anions that further assemble with three additional tungstate units to form a tetramer species with C{sub 2} symmetry. The photoluminescent properties of 3a and 6a were investigated following photoexcitation at room temperature. The magnetic properties of 3a, 4a, 5a and 6a were investigated at room temperature, the complexes exhibiting paramagnetic behaviour. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Electrochemical properties of a new nanocrystalline NaMn{sub 2}O{sub 4} cathode for rechargeable sodium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Moni Kanchan, E-mail: mkd16@pitt.edu [Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Kuruba, Ramalinga [Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Jampani, Prashanth H. [Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Chung, Sung Jae [Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Saha, Partha [Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Epur, Rigved [Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Kadakia, Karan; Patel, Prasad [Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Gattu, Bharat [Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Manivannan, Ayyakkannu [US Department of Energy, National Energy Technology Laboratory, Morgantown, WV 26507 (United States); Kumta, Prashant N., E-mail: pkumta@pitt.edu [Bioengineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Center for Complex Engineered Multifunctional Materials, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Chemical and Petroleum Engineering, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); Mechanical Engineering and Materials Science, Swanson School of Engineering, University of Pittsburgh, PA 15261 (United States); School of Dental Medicine, University of Pittsburgh, PA 15261 (United States)

    2014-10-15

    Highlights: • Nanocrystalline NaMn{sub 2}O{sub 4} exhibiting a new crystalline form has been synthesized by high energy mechanical milling. • Mechanical milling for 20 h directly results in nanocrystalline NaMn{sub 2}O{sub 4}. • Thermally treated oxide shows ∼95 mAh/g capacity in the 24.5 V window. • Capacities from ∼75 to 95 mAh/g obtained with varying voltage windows. • Oxide exhibits 0.3%/cycle fade in capacity when cycled in the 24 V window. - Abstract: Nanocrystalline NaMn{sub 2}O{sub 4} with a crystallite size of ∼8–10 nm exhibiting a new close packed hexagonal crystalline form, different from the known stable orthorhombic (Pbam or Pmnm symmetry) or monoclinic structures common to the Na–Mn–O system, has been synthesized by a high energy mechano-chemical milling process (HEMM) using Na{sub 2}O{sub 2} and Mn{sub 2}O{sub 3} as starting materials. The newly synthesized structure of NaMn{sub 2}O{sub 4} has been studied as a cathode for sodium ion rechargeable batteries. The HEMM derived NaMn{sub 2}O{sub 4} shows a 1st cycle discharge capacity ∼75 mAh/g, ∼86 mAh/g and ∼95 mAh/g when cycled at a rate of ∼40 mA/g in the potential window ∼2.0–4.0 V, ∼24.2 V and ∼24.5 V, respectively. The nanostructured NaMn{sub 2}O{sub 4} shows a fade in capacity of 0.3% per cycle and a moderate rate capability when cycled in the potential window 24 V. However, electrolyte decomposition occurring during charging of the electrode above ∼3.8 V needs to be resolved in order utilize the full capacity of NaMn{sub 2}O{sub 4} as well as improve the stability of the electrode.

  2. 6a-Nitro-6-(2,2,7,7-tetramethyltetrahydro-3aH-bis[1,3]dioxolo[4,5-b:4′,5′-d]pyran-5-yl-6a,6b,7,8,9,11a-hexahydro-6H-spiro[chromeno[3,4-a]pyrrolizine-11,11′-indeno[1,2-b]quinoxaline

    Directory of Open Access Journals (Sweden)

    T. Anuradha

    2014-01-01

    Full Text Available In the title compound, C39H38N4O8, the quinoxaline and indene subunits are essentially planar, with maximum deviations of 0.071 (2 and 0.009 (2 Å, respectively. The indenoquinoxaline system forms a dihedral angle of 72.81 (3° with the chromenopyrrolizine system. The two dioxolane rings, as well as the pyran ring of the chromeno group and the terminal pyrrolizine, each adopt an envelope conformation with O and C as flap atoms. The central pyrrolizine ring adopts a twisted conformation. Intramolecular C—H...O and C—H...N hydrogen bonds occur. The crystal structure exhibits C—H...O hydrogen bonds, and is further stablized by C—H...π interactions, forming a two-dimensional network along the bc plane.

  3. EXAFS and EPR study of La0.6Sr0.2Ca0.2MnO3 and La0.6Sr0.2Ba0.2MnO3

    International Nuclear Information System (INIS)

    Yang, D.-K.Dong-Seok; Ulyanov, A.N.; Phan, Manh-Huong; Kim, Ikgyun; Ahn, Byong-Keun; Rhee, Jang Roh; Kim, Jung Sun; Nguyen, Chau; Yu, Seong-Cho

    2003-01-01

    Extended X-ray absorption fine structure (EXAFS) analysis and electron-paramagnetic resonance (EPR) have been used to examine the local structure and the internal dynamics of La 0.6 Sr 0.2 Ca 0.2 MnO 3 and La 0.6 Sr 0.2 Ba 0.2 MnO 3 lanthanum manganites. The Mn-O bond distance (∼1.94 Angst for both samples) and the Debye-Waller factors (0.36x10 -2 and 0.41x10 -2 Angst 2 for La 0.6 Sr 0.2 Ca 0.2 MnO 3 and for La 0.6 Sr 0.2 Ba 0.2 MnO 3 , respectively) were obtained from the EXAFS analysis. The dependence of the EPR line width on dopant kind (Ca or Ba) showed a decrease of the spin-lattice interaction with an increase of the Curie temperature. For both compositions, the EPR line intensity followed the exponential law I(T)=I 0 exp(E a /k B T), deduced on the basis of the adiabatic polaron hopping model

  4. Crystal structure of 4-(4-chlorophenyl-6-(morpholin-4-ylpyridazin-3(2H-one

    Directory of Open Access Journals (Sweden)

    Abdullah Aydın

    2015-08-01

    Full Text Available In the title compound, C14H14ClN3O2, the morpholine ring adopts a chair conformation, with the exocyclic N—C bond in an equatorial orientation. The 1,6-dihydropyridazine ring is essentially planar, with a maximum deviation of 0.014 (1 Å, and forms a dihedral angle of 40.16 (7° with the plane of the benzene ring. In the crystal, pairs of centrosymmetrically related molecules are linked into dimers via N—H...O hydrogen bonds, forming R22(8 ring motifs. The dimers are connected via C—H...O and C—H...Cl hydrogen bonds, forming a three-dimensional network. Aromatic π–π stacking interactions [centroid–centroid distance = 3.6665 (9 Å] are also observed. Semi-empirical molecular orbital calculations were carried out using the AM1 method. The calculated dihedral angles between the pyridizine and benzene rings and between the pyridizine and morpholine (all atoms rings are 34.49 and 76.96°, respectively·The corresponding values obtained from the X-ray structure determination are 40.16 (7 and 12.97 (9°, respectively. The morpholine ring of the title compound in the calculated gas-phase seems to have a quite different orientation compared to that indicated by the X-ray structure determination.

  5. The design of an Fe-12Mn-O.2Ti alloy steel for low temperature use

    Science.gov (United States)

    Hwang, S. K.; Morris, J. W., Jr.

    1977-01-01

    An investigation was made to improve the low temperature mechanical properties of Fe-8 approximately 12% Mn-O 2Ti alloy steels. A two-phase(alpha + gamma) tempering in combination with cold working or hot working was identified as an effective treatment. A potential application as a Ni-free cryogenic steel was shown for this alloy. It was also shown that an Fe-8Mn steel could be grain-refined by a purely thermal treatment because of its dislocated martensitic structure and absence of epsilon phase. A significant reduction of the ductile-brittle transition temperature was obtained in this alloy. The nature and origin of brittle fracture in Fe-Mn alloys were also investigated. Two embrittling regions were found in a cooling curve of an Fe-12Mn-O 2Ti steel which was shown to be responsible for intergranular fracture. Auger electron spectroscopy identified no segregation during solution-annealing treatment. Avoiding the embrittling zones by controlled cooling led to a high cryogenic toughness in a solution-annealed condition.

  6. Enthalpies of formation of layered LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} (0 ≤ x ≤ 0.5) compounds as lithium ion battery cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Masoumi, Maryam; Cupid, Damian M.; Reichmann, Thomas L.; Seifert, Hans J. [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany). Inst. for Applied Materials - Applied Materials Physics; Chang, Keke; Music, Denis; Schneider, Jochen M. [RWTH Aachen Univ. (Germany). Materials Chemistry

    2017-11-15

    Layer-structured mixed transition metal oxides with the formula LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} (0 ≤ x ≤ 0.5) are considered as important cathode materials for lithium-ion batteries. In an effort to evaluate the relative thermodynamic stabilities of individual compositions in this series, the enthalpies of formation of selected stoichiometries are determined by high temperature oxide melt drop solution calorimetry and verified by ab-initio calculations. The measured and calculated data are in good agreement with each other, and the results show that LiCoO{sub 2}-LiNi{sub 0.5}Mn{sub 0.5}O{sub 2} solid solution approaches ideal behavior. By increasing x, i.e. by equimolar substitution of Mn{sup 4+} and Ni{sup 2+} for Co{sup 3+}, the enthalpy of formation of LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} from the elements becomes more exothermic, implying increased energetic stability. This conclusion is in agreement with the literature results showing improved structural stability and cycling performance of Ni/Mn-rich LiNi{sub x}Mn{sub x}Co{sub 1-2x}O{sub 2} compounds cycled to higher cut-off voltages.

  7. Selective deintercalation of apex over face-shared oxide ions in the topotactic reduction of Sr7Mn4O15 to Sr7Mn4O12.

    Science.gov (United States)

    Hayward, M A

    2004-01-21

    Sodium hydride selectively deintercalates the apex rather than face-shared oxide ions within the structure of Sr(7)Mn(4)O(15) leading to the formation of the structurally related reduced phase Sr(7)Mn(4)O(12).

  8. Synthetic Cu0.507(5)Pb8.73(9)Sb8.15(8)I1.6S20.0(2) nanowires

    International Nuclear Information System (INIS)

    Kryukova, Galina N.; Heuer, Matthias; Wagner, Gerald; Doering, Thomas; Bente, Klaus

    2005-01-01

    Nanowires of an iodine containing Pb-Sb-sulfosalt have been synthesized by chemical vapor transport. Their structure was studied using high-resolution transmission electron microscopy and X-ray powder diffraction. The lattice parameters show values equal to a=4.9801(4)nm, b=0.41132(8)nm (with two-fold superstructure), c=2.1989(1)nm and β=99.918(6) o . These parameters and the results of a multislice simulation are in good agreement with the mineral pillaite, Cu 0.10 Pb 9.16 Sb 9.84 S 22.94 Cl 1.06 O 0.5 (space group C2/m, a=4.949(1)nm, b=0.41259(8)nm, c=2.1828(4)nm, and β=99.62(3) o ). Microprobe and EDX analyses yielded a chemical composition of Cu 0.507(5) Pb 8.73(9) Sb 8.15(8) I 1.6 S 20.0(2) which is close to natural pillaite but contains no oxygen and iodine instead of chlorine. The structure of the investigated material is based on chains of M-S polyhedra (M=Pb or Sb) typical for the architecture of sulfosalts implying iodine atoms in trigonal prismatic coordination with Pb atoms from the M-S polyhedra of neighboring chains. The [010] superstructure of the specimen was found to be unstable under electron beam irradiation with a rapid decrease of the b lattice parameter from 0.8 to 0.4nm within 5min

  9. Multireversible redox processes in pentanuclear bis(triple-helical) manganese complexes featuring an oxo-centered triangular {Mn(II)2Mn(III)(μ3-O)}5+ or {Mn(II)Mn(III)2(μ3-O)}6+ core wrapped by two {Mn(II)2(bpp)3}-.

    Science.gov (United States)

    Romain, Sophie; Rich, Jordi; Sens, Cristina; Stoll, Thibaut; Benet-Buchholz, Jordi; Llobet, Antoni; Rodriguez, Montserrat; Romero, Isabel; Clérac, Rodolphe; Mathonière, Corine; Duboc, Carole; Deronzier, Alain; Collomb, Marie-Noëlle

    2011-09-05

    A new pentanuclear bis(triple-helical) manganese complex has been isolated and characterized by X-ray diffraction in two oxidation states: [{Mn(II)(μ-bpp)(3)}(2)Mn(II)(2)Mn(III)(μ-O)](3+) (1(3+)) and [{Mn(II)(μ-bpp)(3)}(2)Mn(II)Mn(III)(2)(μ-O)](4+) (1(4+)). The structure consists of a central {Mn(3)(μ(3)-O)} core of Mn(II)(2)Mn(III) (1(3+)) or Mn(II)Mn(III)(2) ions (1(4+)) which is connected to two apical Mn(II) ions through six bpp(-) ligands. Both cations have a triple-stranded helicate configuration, and a pair of enantiomers is present in each crystal. The redox properties of 1(3+) have been investigated in CH(3)CN. A series of five distinct and reversible one-electron waves is observed in the -1.0 and +1.50 V potential range, assigned to the Mn(II)(4)Mn(III)/Mn(II)(5), Mn(II)(3)Mn(III)(2)/Mn(II)(4)Mn(III), Mn(II)(2)Mn(III)(3)/Mn(II)(3)Mn(III)(2), Mn(II)Mn(III)(4)/Mn(II)(2)Mn(III)(3), and Mn(III)(5)/Mn(II)Mn(III)(4) redox couples. The two first oxidation processes leading to Mn(II)(3)Mn(III)(2) (1(4+)) and Mn(II)(2)Mn(III)(3) (1(5+)) are related to the oxidation of the Mn(II) ions of the central core and the two higher oxidation waves, close in potential, are thus assigned to the oxidation of the two apical Mn(II) ions. The 1(4+) and 1(5+) oxidized species and the reduced Mn(4)(II) (1(2+)) species are quantitatively generated by bulk electrolyses demonstrating the high stability of the pentanuclear structure in four oxidation states (1(2+) to 1(5+)). The spectroscopic characteristics (X-band electron paramagnetic resonance, EPR, and UV-visible) of these species are also described as well as the magnetic properties of 1(3+) and 1(4+) in solid state. The powder X- and Q-band EPR signature of 1(3+) corresponds to an S = 5/2 spin state characterized by a small zero-field splitting parameter (|D| = 0.071 cm(-1)) attributed to the two apical Mn(II) ions. At 40 K, the magnetic behavior is consistent for 1(3+) with two apical S = 5/2 {Mn(II)(bpp)(3)}(-) and one S

  10. Comparison of the cytokine immune response to pathogenic Yersinia enterocolitica bioserotype 1B/O:8 and 2/O:9 in susceptible BALB/C and resistant C57BL/6 mice.

    Science.gov (United States)

    Wang, Xin; Gu, Wenpeng; Qiu, Haiyan; Xia, Shengli; Zheng, Han; Xiao, Yuchun; Liang, Junrong; Jing, Huaiqi

    2013-10-01

    We investigated the lethality of pathogenic Yersinia enterocolitica bioserotypes 1B/O:8 and 2/O:9 in susceptible BALB/C and resistant C57BL/6 mice; the cytokine alterations and histopathological changes were observed comparing the two strains in BALB/C mice. The data showed the 50% lethal dose (LD50) for the pathogenic Y. enterocolitica bioserotype 1B/O:8 was 10³ cfu in both BALB/C and C57BL/6 mice; while the LD50 for the 2/O:9 was 10⁸ cfu in BALB/C mice and 10⁹ cfu in C57BL/6 mice, a large difference. After infection with the two strains in BALB/C mice, GM-CSF (granulocyte-macrophage colony stimulating factor), IFN-γ (interferon-γ), IL-1β (interleukin-1β), IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, and TNF-α (tumor necrosis factor-α) appeared as a cytokine storm in a short period, reached peak values, and then quickly decreased. This appeared important for the immune response and cytokine immunopathogenesis in pathogenic Y. enterocolitica infections. In the initial infection stage, GM-CSF, IL-6, and TNF-α of 2/O:9 were higher than 1B/O:8; and subsequently the status was reversed. However, levels of IFN-γ, IL-1β, IL-2, IL-4, IL-5, IL-10, IL-12 following infection with 1B/O:8 were always higher than with 2/O:9. The histopathological changes in the liver and spleen in BALB/C mice infected with the two strains were similar at different times and doses. These observations show the different immunological effects and changes for pathogenic Y. enterocolitica 1B/O:8 and 2/O:9 infections using the mouse model. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Crystal structure and luminescence properties of Bi{sup 3+}activated Ca{sub 2}Y{sub 8}(SiO{sub 4}){sub 6}O{sub 2} phosphors under near UV excitation

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Zhihua [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xian Jiaotong University, Xian 710049, ShannXi (China); International Center for Dielectric Research, Xian Jiaotong University, Xian 710049, ShannXi (China); School of Materials Science and Engineer, Chang’an University, Xi’an 710061, ShannXi (China); Wang, Minqiang, E-mail: mqwang@mail.xjtu.edu.cn [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xian Jiaotong University, Xian 710049, ShannXi (China); International Center for Dielectric Research, Xian Jiaotong University, Xian 710049, ShannXi (China); Yang, Zhi [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education, Xian Jiaotong University, Xian 710049, ShannXi (China); International Center for Dielectric Research, Xian Jiaotong University, Xian 710049, ShannXi (China); Liu, Kaiping; Zhu, Feiyan [School of Materials Science and Engineer, Chang’an University, Xi’an 710061, ShannXi (China)

    2016-07-15

    Oxyapatite Ca{sub 2}Y{sub 8−x}(SiO{sub 4}){sub 6}O{sub 2}:xBi{sup 3+}phosphor has been prepared via high temperature solid-state reaction. Its crystal structure and PL properties were investigated by X-ray diffraction, photoluminescence excitation and emission spectra. The results indicated that the Ca{sub 2}Y{sub 8}(SiO{sub 4}){sub 6}O{sub 2} crystallizes as a hexagonal structure with a space group of P6{sub 3}/m and lattice constants of a=b=9.3507 Å, c=6.7899 Å, α=β=90.00°, γ=120.00°, V=514.14 Å{sup 3}; The phosphor has two prominent emission bands: when excited under 320–360 nm, the phosphors emit a broad band centered at 495 nm due to the {sup 3}P{sub 1}–{sup 1}S{sub 0} transition of Bi{sup 3+} in 4f (C{sub 3}) sites; when excited under 380 nm, the phosphors emit a broad band centered at 411 nm due to the {sup 3}P{sub 1}–{sup 1}S{sub 0} transition of Bi{sup 3+} in 6h (C{sub s}) sites. The emission color varies from the greenish blue to blue as the excitation wavelength increases from 335 to 380 nm. The optimal intensity of emission band was observed when x=0.015 in the Ca{sub 2}Y{sub 8−x}(SiO{sub 4}){sub 6}O{sub 2}:xBi{sup 3+} series. The average critical distance Rc among Bi{sup 3+} ions is determined to be 20.15 Å.

  12. La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2}. Synthesis, structure and {sup 31}P solid state NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, Timo; Eul, Matthias; Poettgen, Rainer [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Benndorf, Christopher; Eckert, Hellmut [Muenster Univ. (Germany). Inst. fuer Physikalische Chemie; Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. of Physics

    2016-04-01

    The phosphide oxides La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2} were synthesized from lanthanum, copper(I) oxide, red phosphorus, and lanthanum(III) chloride through a ceramic technique. Single crystals can be grown in a NaCl/KCl flux. Both structures were refined from single crystal X-ray diffractometer data: I4/mmm, a = 403.89(4), c = 2681.7(3) pm, wR2 = 0.0660, 269 F{sup 2} values, 19 variables for La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} and a = 407.52(5), c = 4056.8(7) pm, wR2 = 0.0905, 426 F{sup 2} values, 27 variables for La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2}. Refinement of the occupancy parameters revealed full occupancy for the oxygen sites in both compounds. The structures are composed of cationic (La{sub 2}O{sub 2}){sup 2+} layers and covalently bonded (Cu{sub 4}P{sub 4}){sup 5-} polyanionic layers with metallic characteristics, and an additional La{sup 3+} between two adjacent (Cu{sub 4}P{sub 4}){sup 5-} layers. The structure of La{sub 5}Cu{sub 4}P{sub 4}O{sub 4}Cl{sub 2} comprises two additional LaOCl slabs per unit cell. Temperature-dependent magnetic susceptibility studies revealed Pauli paramagnetism. The phosphide substructure of La{sub 3}Cu{sub 4}P{sub 4}O{sub 2} was studied by {sup 31}P solid state NMR spectroscopy. By using a suitable dipolar re-coupling approach the two distinct resonances belonging to the P{sub 2}{sup 4-} and the P{sup 3-} units could be identified.

  13. A facile route to synthesize multiporous MnCo2O4 and CoMn2O4 spinel quasi-hollow spheres with improved lithium storage properties

    Science.gov (United States)

    Li, Jingfa; Xiong, Shenglin; Li, Xiaowei; Qian, Yitai

    2013-02-01

    A facile and general way for the synthesis of porous and hollow complex oxides is highly desirable owing to their significant applications for energy storage and other fields. In this contribution, uniform Mn0.33Co0.67CO3 and Co0.33Mn0.67CO3 microspheres are firstly fabricated solvothermally just by tuning the molar ratio of Mn and Co. Subsequently, the growth of multiporous MnCo2O4 and CoMn2O4 quasi-hollow microspheres by topotactic chemical transformation from the corresponding precursors are realized through a non-equilibrium heat treatment process. Topotactic conversion further demonstrated that the much larger CoMn2O4 pores than those of MnCo2O4 are possibly due to the longer transfer distance of ions. When evaluated as anode materials for LIBs (lithium ion batteries), after 25 cycles at a current density of 200 mA g-1, the resultant MnCo2O4 and CoMn2O4 quasi-hollow microspheres possessed reversible capacities of 755 and 706 mA h g-1, respectively. In particular, the MnCo2O4 samples could deliver a reversible capacity as high as 610 mA h g-1 even at a higher current density of 400 mA g-1 with excellent electrochemical stability after 100 cycles of testing, indicating its potential application in LIBs. We believe that such good performance results from the appropriate pore size and quasi-hollow nature of MnCo2O4 microspheres, which can effectively buffer the large volume variation of anodes based on the conversion reaction during Li+ insertion/extraction. The present strategy is simple but very effective, and due to its versatility, it can be extended to other binary, even ternary complex metal oxides with high-performance in LIBs.A facile and general way for the synthesis of porous and hollow complex oxides is highly desirable owing to their significant applications for energy storage and other fields. In this contribution, uniform Mn0.33Co0.67CO3 and Co0.33Mn0.67CO3 microspheres are firstly fabricated solvothermally just by tuning the molar ratio of Mn and Co

  14. 2,6-Bis(2-hydroxyethyl-8b,8c-diphenylperhydro-2,3a,4a,6,7a,8a-hexaazacyclopenta[def]fluorene-4,8-dithione

    Directory of Open Access Journals (Sweden)

    Zihua Wang

    2009-06-01

    Full Text Available In the title molecule, C24H28N6O2S2, the dihedral angle between the aromatic ring planes is 42.2 (1°. In the crystal structure, the hydroxy groups are involved in O—H...S hydrogen bonding, which links the molecules into corrugated layers propagating parallel to the bc plane.

  15. Study by X-ray diffraction of structure modifications induced by pressure in different actinide compounds: AnO2 dioxides (An=Th, Pu, Am), AnCl4 tetrachlorides (An=Th, U), UBx borides (x=2,4,12) and the carbide UC2

    International Nuclear Information System (INIS)

    Dancausse, J.P.

    1991-01-01

    Structural transitions, induced by pressure, of actinide compounds are studied by X-ray diffraction, the determination of incompressibility is also studied at atmospheric pressure. The crystal structure of ThO 2 , PuO 2 and AmO 2 evolves, near 40 MPa from a fcc lattice to an orthorhombic lattice. Incompressibility values associated to UO 2 and NpO 2 incompressibility evidence an important discontinuity between UO 2 and NpO 2 and other dioxides due to their different electronic structure. Tetragonal ThCl 4 and UCl 4 undergo a structure transition respectively at 2 and 5 GPa. UCl 4 becomes monoclinic and its color changes. At higher pressure these compounds become progressively amorphous. The crystal structure of uranium borides is not changed up to 50 GPa. UC 2 presents a phase transition at 17.6 GPa from a tetragonal to a hexagonal lattice

  16. Design, synthesis and luminescence properties of Ba2 YB2 O6 Cl- and Ba2 YB2 O6 F-based phosphors.

    Science.gov (United States)

    Chen, Wanping; Yang, Xin; Liu, Yan; Dai, Xiaoyan

    2015-05-01

    Using a high-temperature solid-state reaction, the chlorine in Ba2 YB2 O6 Cl is gradually replaced by F, and a new compound with the nominal chemical formula Ba2 YB2 O6 F and two phosphors doped with Ce(3+) and Eu(3+) , respectively, are obtained. X-Ray diffraction and photoluminescence spectroscopy are used to characterize the as-synthesized samples. The as-synthesized Ba2 YB2 O6 Cl exhibits bright blue emission in the spectral range ~ 330-410 nm with a maximum around 363 nm under X-ray or UV excitation. Ba2 YB2 O6 F:0.01Ce(3+) exhibits blue emission in the range ~ 340-570 nm with a maximum around 383 nm. Ba2 YB2 O6 F:0.01Eu(3+) exhibits a predominantly (5) D0 -(7)  F2 emission (~610 nm) and the relative intensities of the (5) D0 -(7)  F0,1,2 emissions are tunable under different wavelength UV excitation. The luminescence behaviors of the two phosphors are explained simply in terms of the host composition and site occupancy probability of Ce(3+) and Eu(3+) , respectively. The results indicate that these phosphors have potential application as a blue phosphor or as a red phosphor. Copyright © 2014 John Wiley & Sons, Ltd.

  17. 2,8,15,18,21,24,31,37,44,47,50,53-Dodecaoxaheptacyclo[52.4.0.04,35.06,33.09,14.025,30.038,43]octapentaconta-1(54,4,6(33,9(14,10,12,25(30,26,28,34,38(43,39,41,55,57-pentadecaene dichloromethane disolvate

    Directory of Open Access Journals (Sweden)

    Ji Ye Yun

    2014-05-01

    Full Text Available In the title compound, C46H50O12·2CH2Cl2, each dual 20-crown-6 unit crystallizes with two dichloromethane solvent molecules. The crown unit molecule lies about an inversion centre located at the central benzene ring. The two crown ring groups adopt an anti conformation, stabilized by weak intramolecular C—H...O interactions. In the crystal, the crown unit molecules and the solvent molecules are linked by C—H...O interactions into a three-dimensional network.

  18. Binding of higher alcohols onto Mn(12) single-molecule magnets (SMMs): access to the highest barrier Mn(12) SMM.

    Science.gov (United States)

    Lampropoulos, Christos; Redler, Gage; Data, Saiti; Abboud, Khalil A; Hill, Stephen; Christou, George

    2010-02-15

    Two new members of the Mn(12) family of single-molecule magnets (SMMs), [Mn(12)O(12)(O(2)CCH(2)Bu(t))(16)(Bu(t)OH)(H(2)O)(3)].2Bu(t)OH (3.2Bu(t)OH) and [Mn(12)O(12)(O(2)CCH(2)Bu(t))(16)(C(5)H(11)OH)(4)] (4) (C(5)H(11)OH is 1-pentanol), are reported. They were synthesized from [Mn(12)O(12)(O(2)CMe)(16)(H(2)O)(4)].2MeCO(2)H.4H(2)O (1) by carboxylate substitution and crystallization from the appropriate alcohol-containing solvent. Complexes 3 and 4 are new members of the recently established [Mn(12)O(12)(O(2)CCH(2)Bu(t))(16)(solv)(4)] (solv = H(2)O, alcohols) family of SMMs. Only one bulky Bu(t)OH can be accommodated into 3, and even this causes significant distortion of the [Mn(12)O(12)] core. Variable-temperature, solid-state alternating current (AC) magnetization studies were carried out on complexes 3 and 4, and they established that both possess an S = 10 ground state spin and are SMMs. However, the magnetic behavior of the two compounds was found to be significantly different, with 4 showing out-of-phase AC peaks at higher temperatures than 3. High-frequency electron paramagnetic resonance (HFEPR) studies were carried out on single crystals of 3.2Bu(t)OH and 4, and these revealed that the axial zero-field splitting constant, D, is very different for the two compounds. Furthermore, it was established that 4 is the Mn(12) SMM with the highest kinetic barrier (U(eff)) to date. The results reveal alcohol substitution as an additional and convenient means to affect the magnetization relaxation barrier of the Mn(12) SMMs without major change to the ligation or oxidation state.

  19. Effects of synthesis conditions on structure and surface properties of SmMn{sub 2}O{sub 5} mullite-type oxide

    Energy Technology Data Exchange (ETDEWEB)

    Thampy, Sampreetha; Ibarra, Venessa; Lee, Yun-Ju [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); McCool, Geoffrey [Nanostellar Inc., 3696 Haven Avenue, Redwood City, CA 94063 (United States); Cho, Kyeongjae [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Hsu, Julia W.P., E-mail: jwhsu@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2016-11-01

    Highlights: • Investigate the effects of calcination temperature and precipitation pH on crystallinity, phase purity, particle size, surface composition, and NO adsorption capacity of SmMn{sub 2}O{sub 5}. • High calcination temperature increases mullite phase purity but decreases specific surface area (SSA). • Mullite phase purity is independent of pH while SSA monotonically increases. • SSA and surface Mn/Sm ratio determine NO uptake. - Abstract: A mixed-phase compound that contains SmMn{sub 2}O{sub 5} mullite-type oxides has been reported to display excellent catalytic activity for nitric oxide (NO) oxidation. Here we investigate the effects of calcination temperature and precipitation pH on structural, physical, chemical, and surface properties of SmMn{sub 2}O{sub 5}. As the calcination temperature increases from 750 °C to 1000 °C, mullite phase purity increases from 74% to 100%, while specific surface area (SSA) decreases from 23.6 m{sup 2}/g to 5.1 m{sup 2}/g with particle size increases correspondingly. Mullite phase purity (87%) is independent of pH between 8.5–10.4, whereas SSA monotonically increases from 12.5 m{sup 2}/g at pH 8.1 to 27.4 m{sup 2}/g at pH 13. X-ray photoelectron spectroscopy (XPS) studies reveal that the surface Mn/Sm ratio is similar to the bulk value and is unaffected by calcination temperature and pH values up to 10.4, whereas sample precipitated at pH 13 is surface-rich in Sm. NO chemisorption studies show that the SSA and surface Mn/Sm ratio determine NO uptake by SmMn{sub 2}O{sub 5} mullite oxides.

  20. Calibration setting numbers for dose calibrators for the PET isotopes "5"2Mn, "6"4Cu, "7"6Br, "8"6Y, "8"9Zr, "1"2"4I

    International Nuclear Information System (INIS)

    Wooten, A. Lake; Lewis, Benjamin C.; Szatkowski, Daniel J.; Sultan, Deborah H.; Abdin, Kinda I.; Voller, Thomas F.; Liu, Yongjian; Lapi, Suzanne E.

    2016-01-01

    For PET radionuclides, the radioactivity of a sample can be conveniently measured by a dose calibrator. These devices depend on a “calibration setting number”, but many recommended settings from manuals were interpolated based on standard sources of other radionuclide(s). We conducted HPGe gamma-ray spectroscopy, resulting in a reference for determining settings in two types of vessels containing one of several PET radionuclides. Our results reiterate the notion that in-house, experimental calibrations are recommended for different radionuclides and vessels. - Highlights: • Dose calibrators measure radioactivity by ionization of gas from emitted radiation. • Accuracy of dose calibrators depends on “calibration setting numbers” for isotopes. • Many manufacturer settings are interpolated from emissions of other radionuclides. • As a high-precision reference, HPGe gamma-ray spectroscopy was conducted. • New calibrations were found for PET isotopes "5"2Mn, "6"4Cu, "7"6Br, "8"6Y, "8"9Zr, and "1"2"4I.

  1. Structural Defects of Silver Hollandite, Ag(x)Mn8O(y), Nanorods: Dramatic Impact on Electrochemistry.

    Science.gov (United States)

    Wu, Lijun; Xu, Feng; Zhu, Yimei; Brady, Alexander B; Huang, Jianping; Durham, Jessica L; Dooryhee, Eric; Marschilok, Amy C; Takeuchi, Esther S; Takeuchi, Kenneth J

    2015-08-25

    Hollandites (OMS-2) are an intriguing class of sorbents, catalysts, and energy storage materials with a tunnel structure permitting one-dimensional insertion and deinsertion of ions and small molecules along the c direction. A 7-fold increase in delivered capacity for Li/AgxMn8O16 electrochemical cells (160 versus 23 mAh/g) observed upon a seemingly small change in silver content (x ∼1.1 (L-Ag-OMS-2) and 1.6 (H-Ag-OMS-2)) led us to characterize the structure and defects of the silver hollandite material. Herein, Ag hollandite nanorods are studied through the combined use of local (atomic imaging, electron diffraction, electron energy-loss spectroscopy) and bulk (synchrotron based X-ray diffraction, thermogravimetric analysis) techniques. Selected area diffraction and high resolution transmission electron microscopy show a structure consistent with that refined by XRD; however, the Ag occupancy varies significantly even within neighboring channels. Both local and bulk measurements indicate a greater quantity of oxygen vacancies in L-Ag-OMS-2, resulting in lower average Mn valence relative to H-Ag-OMS-2. Electron energy loss spectroscopy shows a lower Mn oxidation state on the surface relative to the interior of the nanorods, where the average Mn valence is approximately Mn(3.7+) for H-Ag-OMS-2 and Mn(3.5+) for L-Ag-OMS-2 nanorods, respectively. The higher delivered capacity of L-Ag-OMS-2 may be related to more oxygen vacancies compared to H-Ag-OMS-2. Thus, the oxygen vacancies and MnO6 octahedra distortion are assumed to open the MnO6 octahedra walls, facilitating Li diffusion in the ab plane. These results indicate crystallite size and surface defects are significant factors affecting battery performance.

  2. Metal-assisted chemical etching in HF/Na2S2O8 OR HF/KMnO4 produces porous silicon

    NARCIS (Netherlands)

    Hadjersi, T.; Gabouze, N.; Kooij, Ernst S.; Zinine, A.; Zinine, A.; Ababou, A.; Chergui, W.; Cheraga, H.; Belhousse, S.; Djeghri, A.

    2004-01-01

    A new metal-assisted chemical etching method using Na2S2O8 or KMnO4 as an oxidizing agent was proposed to form a porous silicon layer on a highly resistive p-type silicon. A thin layer of Ag or Pd is deposited on the Si(100) surface prior to immersion in a solution of HF and Na2S2O8 or HF and KMnO4.

  3. Complexation in the system K2SeO4-UO2SeO4-H2O

    International Nuclear Information System (INIS)

    Serezhkina, L.B.; Kuchumova, N.V.; Serezhkin, V.N.

    1994-01-01

    Complexation in the system K 2 SeO 4 -UO 2 SeO 4 -H 2 O at 25 degrees C is studied by isothermal solubility. Congruently soluble K 2 UO 2 (SeO 4 ) 2 ·4H 2 O (I) and incongruently soluble K 2 (UO 2 ) 2 (SeO 4 ) 3 ·6H 2 O (II) are observed. The unit-cell constants of I and II are determined from an X-ray diffraction investigation. For I, a = 12,969, b = 11.588, c = 8.533 angstrom, Z = 4, space group Pmmb. For II, a = 23.36, b = 6.784, c = 13.699 angstrom, β = 104.42 degrees, Z = 4, space group P2/m, P2, or Pm. Complexes I and II are representatives of the crystal-chemical groups AB 2 2 M 1 and A 2 T 3 3 M 1 , respectively, of uranyl complexes

  4. Magnetism and superconductivity in Ru{sub 1-x}Sr{sub 2}RECu{sub 2+x}O{sub 8-d} (RE=Gd, Eu) and RuSr{sub 2}Gd{sub 1-y}Ce{sub y}Cu{sub 2}O{sub 8} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Klamut, P.W. [Dept. of Physics, Northern Illinois Univ., DeKalb, IL (United States)]|[Inst. of Low Temperature and Structure Research of Polish Academy of Sciences, Wroclaw (Poland); Dabrowski, B.; Mini, S.M.; Kolesnik, S.; Maxwell, M.; Mais, J. [Dept. of Physics, Northern Illinois Univ., DeKalb, IL (United States); Shengelaya, A.; Keller, H. [Physik-Inst., Univ. Zuerich, Zuerich (Switzerland); Khazanov, R. [Physik-Inst., Univ. Zuerich, Zuerich (Switzerland)]|[Lab. for Muon-Spin Spectroscopy, Paul Scherrer Inst., Villigen PSI (Switzerland); Savic, I. [Physik-Inst., Univ. Zuerich, Zuerich (Switzerland)]|[Faculty of Physics, Univ. of Belgrade, Belgrade (Yugoslavia); Sulkowski, C.; Wlosewicz, D.; Matusiak, M. [Inst. of Low Temperature and Structure Research of Polish Academy of Sciences, Wroclaw (Poland); Wisniewski, A.; Puzniak, R.; Fita, I. [Inst. of Physics of Polish Academy of Sciences, Warszawa (Poland)

    2002-07-01

    We discuss the properties of new superconducting compositions of ruthenocuprates Ru{sub 1-x}Sr{sub 2}RECu{sub 2+x}O{sub 8-d} (RE=Gd, Eu) that were synthesized at 600 atm. of oxygen at 1080 C. By changing ratio between the Ru and Cu, the temperature of superconducting transition (T{sub C}) raises up to T{sub C}{sup max} = 72 K for x=0.3, 0.4. The hole doping achieved along the series increases with Cu{yields}Ru substitution. For x {ne} 0, T{sub C} can be subsequently tuned between T{sub C}{sup max} and 0 K by changing oxygen content in the compounds. The magnetic characteristics of the RE=Gd and Eu based compounds are interpreted as indicative of constrained dimensionality of the superconducting phase. Muon spin rotation experiments reveal the presence of the magnetic transitions at low temperatures (T{sub m}=14-2 K for x=0.1-0.4) that can originate in the response of Ru/Cu sublattice. RuSr{sub 2}Gd{sub 1-y}Ce{sub 1-y}Cu{sub 2}O{sub 8} (0 {<=} y {<=} 0.1) compounds show the simultaneous increase of T{sub N} and decrease of T{sub C} with y. The effect should be explained by the electron doping that occurs with Ce{yields}Gd substitution. Properties of these two series allow us to propose phase diagram for 1212-type ruthenocuprates that links their properties to the hole doping achieved in the systems. Non-superconducting single-phase RuSr{sub 2}GdCu{sub 2}O{sub 8} and RuSr{sub 2}EuCu{sub 2}O{sub 8} are reported and discussed in the context of the properties of substituted compounds. (orig.)

  5. Hydrothermal synthesis, structures and optical properties of A2Zn3(SeO3)4·XH2O (A=Li, Na, K; X=2 or 0)

    Science.gov (United States)

    Liu, Yunsheng; Mei, Dajiang; Xu, Jingli; Wu, Yuandong

    2015-12-01

    New alkali metal zinc selenites, A2Zn3(SeO3)4·XH2O (A=Li, Na, K; X=2 or 0) were prepared through hydrothermal reactions. Li2Zn3(SeO3)4·2H2O (1) crystallizes in the monoclinic space group P21/c with lattice parameters a=8.123(4), b=9.139(4), c=7.938(3) Å, β=112.838(9)°. Na2Zn3(SeO3)4·2H2O (2) crystallizes in the monoclinic space group C2/c with lattice parameters a=15.7940(18), b=6.5744(8), c=14.6787(17) Å, β=107.396(3)°. K2Zn3(SeO3)4 (3) crystallizes in the monoclinic space group C2/c with lattice parameters a=11.3584(12), b=8.6091(9), c=13.6816(14) Å, β=93.456(2)°. The anionic structures are composed of [Zn3O12]18- sheets, chains, and "isolated" units in compound 1, 2, 3, respectively, and trigonal pyramids SeO32-. The compounds were characterized by the solid state UV-vis-NIR diffuse reflectance spectroscopy, infrared spectra and thermogravimetric analysis.

  6. A New Open-framework Iron Borophosphate from Ionic Liquids: KFe[BP2O8(OH

    Directory of Open Access Journals (Sweden)

    Guangmei Wang

    2011-04-01

    Full Text Available A new open-framework iron borophosphate, KFe[BP2O8(OH], has been obtained by ionothermal synthesis from KH2PO4, FeCl3∙4H2O, H3BO3 and [C4mpyr]Br (1-butyl-1-methylpyrrolidinium bromide. Single-crystal X-ray diffraction analysis shows that KFe[BP2O8(OH] (monoclinic, P21/c, a = 9.372(2 Å , b = 8.146(2Å , c = 9.587(2 Å, β = 101.18(3°, V = 718.0(2Å3 and Z = 4 has a three-dimensional (3-D framework structure composed by {Fe(IIIO5(OH} octahedra as well as {BO3(OH} and {PO4} tetrahedra. As anionic structural sub-unit, KFe[BP2O8(OH], contains an infinite open-branched {[BP2O8(OH]4-} chain which is formed by alternating {BO3(OH} and {PO4} tetrahedra. {Fe(IIIO5(OH} octahedra share common O corners with five phosphate tetrahedra and the OH corner links to the hydrogen borate group to give a 3D framework. The negative charges of the inorganic framework are balanced by K+ ions.

  7. Ab initio investigation of thermodynamic stability and structure of cell molecules B3N4H8 and Be4O4H8

    International Nuclear Information System (INIS)

    Minyaev, R.M.

    2000-01-01

    Ab initio calculation methods (RHF/6-31G, MP2(full)/6-31G and MP2(full)/6-311++G) ) are used to investigate thermodynamic stability, energy and structural characteristics of different position isomers of isoelectron B 3 N 4 H 8 (1) and Be 4 O 4 H 8 (2) systems with cubane structure. High thermodynamic stability of these system is shown. Decomposition of structure (1) into two 1,3,2,4-diazadiborethidine molecules or four molecules of iminoborane HBNH is an endothermal process and needs 10.1 (RHF/6-31G), 39/6 (MP2(full)/6-31G) Cal/mol and 140.6 (RHF/6-31G), 161.4 (MP2(full)/6-31G) Cal/mol accordingly. Decomposition of structure (2) into two 1,3,2,4-dioxydiberyllotidine or four molecules of HBeOH is an endothermal process too and needs 22.1 (RHF/6-31G), 39.8 (MP2(full)/6-31G) Cal/mol and 127.1(RHF/6-31G), 155.2 MP2(full)/6-31G) Cal/mol accordingly. Geometrical characteristics of simple BeH 2 , Be 2 , Be 2 H 2 , Be 2 H 4 , BeO, Be 2 O 2 molecules are calculated [ru

  8. Synthesis, structure and phase separation of a new 12R-type perovskite-related oxide Ba3NdMn2O9

    International Nuclear Information System (INIS)

    Yang, H.; Tang, Y.K.; Yao, L.D.; Zhang, W.; Li, Q.A.; Li, F.Y.; Jin, C.Q.; Yu, R.C.

    2007-01-01

    A new 12R-type perovskite-related oxide, Ba 3 NdMn 2 O 9 , has been prepared by traditional solid-state reaction method and the presence of chemical phase separation phenomenon has been revealed by transmission electron microscopy. The perfect grains of the compound have an average chemical composition of Ba 4 NdMn 3 O 12 (mainly for cationic ratio) according to the characterization by TEM-EDX. In this perfect 12R-type structure with composition Ba 4 NdMn 3 O 12 , the Nd cations are located in the corner-sharing octahedra, whereas the Mn cations are located in the face-sharing octahedra, leading to a remarkable cation ordering. Superstructure modulation was found to be a common phenomenon in the 12R polytype and the modulated areas were revealed by both EDX and EELS to be Nd rich compared to the perfect areas. This result together with the previous work [A.F. Fuentes, K. Boulahya, U. Amador, J. Solid State Chem. 177 (2004) 714] has shown that, for the rare-earth-containing Ba-RE-Mn-O systems (RE being rare-earth elements), the composition Ba 4 REMn 3 O 12 (mainly for cationic ratio) is required for the formation of perfect 12R polytype

  9. Poly[diaquadi-μ-hydroxido-κ4O:O-dinitrato-κ4O:O′-bis[3-(pyridin-4-yl-κN-5-(pyridin-3-yl-1,2,4-oxadiazole]dicopper(II

    Directory of Open Access Journals (Sweden)

    Longfei Wu

    2012-04-01

    Full Text Available The title compound, [Cu2(NO32(OH2(C12H8N4O2(H2O2]n, consists of a neutral polymeric CuII complex in which each CuII atom has a distorted octahedral geometry defined by a pyridyl N atom from a 3-(pyridin-3-yl-5-(pyridin-4-yl-1,2,4-oxadiazole ligand and five O atoms from a water molecule, two nitrates and two hydroxides. Two CuII ions are bridged by two hydroxide anions resulting in a Cu2O2 loop, located across an inversion center and connected by the nitrate anions into a broad two-dimensional polymeric structure parallel to (100. In the crystal, there are O—H...O hydrogen bonds between the coodinated water molecule and the nitrate and hydroxide, and between the hydroxide and the nitrate. Intermolecular π–π interactions are present between pyridine rings in adjacent two-dimensional structures, with a centroid–centroid distance of 3.582 (2 Å.

  10. A Theoretical investigation of a potential high energy density compound 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo[3.1.1.1(2,4]octane

    Directory of Open Access Journals (Sweden)

    Guozheng Zhao

    2013-01-01

    Full Text Available The B3LYP/6-31G (d density functional theory (DFT method was used to study molecular geometry, electronic structure, infrared spectrum (IR and thermodynamic properties. Heat of formation (HOF and calculated density were estimated to evaluate detonation properties using Kamlet-Jacobs equations. Thermal stability of 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo [3.1.1.1(2,4]octane (TTTO was investigated by calculating bond dissociation energy (BDE at the unrestricted B3LYP/6-31G(d level. Results showed the N-NO2 bond is a trigger bond during the thermolysis initiation process. The crystal structure obtained by molecular mechanics (MM methods belongs to P2(1/C space group, with cell parameters a = 8.239 Å, b = 8.079 Å, c = 16.860 Å, Z = 4 and r = 1.922 g cm-3. Both detonation velocity of 9.79 km s-1 and detonation pressure of 44.22 GPa performed similarly to CL-20. According to the quantitative standards of energetics and stability, TTTO essentially satisfies this requirement as a high energy density compound (HEDC.

  11. μ-Adipato-κ2O1:O4-bis{[2,6-bis(1H-benzimidazol-2-yl-κN3pyridine-κN](nitrato-κOlead(II}

    Directory of Open Access Journals (Sweden)

    Lian-Qiang Wei

    2010-01-01

    Full Text Available The dinuclear title compound, [Pb2(C6H8O4(NO32(C19H13N52], lies with the mid-point of the butyl chain of the bridging adipate unit on a center of inversion. The PbII ion is covalently bonded to the nitrate anion and is bonded to a carboxylate group of the adipate unit by another covalent bond. The N-heterocycle functions in a chelating tridentate mode. The metal atom exists in a Ψ-octahedral coordination environment. When weaker Pb...O interactions are also considered, the geometry is a Ψ-tricapped trigonal prism in which the lone-pair electrons occupy one face of the trigonal prism. Adjacent molecules are linked into a layer structure by N—H...O hydrogen bonds.

  12. Keggin type polyoxometalate H4[αSiW12O40].nH2O as intercalant for hydrotalcite

    Directory of Open Access Journals (Sweden)

    Neza Rahayu Palapa

    2017-06-01

    Full Text Available The synthesis of hydrotalcite and polyoxometalate H4[αSiW12O40].nH2O with the ratio (2:1, (1:1, (1:2 and (1:3 has been done. The product of intercalation was characterized using FT-IR spectrophotometer, XRD, and TG-DTA. Polyoxometalate H4[αSiW12O40].nH2O intercalated layered double hydroxide was optimised to use as adsorbent Congo red dye. Characterization using FT-IR was not showing the optimal insertion process. The result using XRD characterization was showed successful of polyoxometalate H4[αSiW12O40].nH2O inserted layered double hydroxide with a ratio (1:1 which the basal spacing was expanded from 7,8 Ȧ to 9,81 Ȧ. Furthermore, the thermal analysis was performed using TG-DTA. The result show that the decomposition of polyoxometalate H4[αSiW12O40].nH2O intercalated  hydrotalcite with ratio (1:1 was occured at 80oC to 400oC with a loss of OH in the layer at 150oC to 220oC, and then the decomposition of the compound polyoxometalate H4[αSiW12O40].nH2O at 350oC to 420oC. Keywords: Hydrotalcite, Layered Double Hydroxide, Polyoxometalate, Intercalation

  13. Topotactic reduction of YBa2Cu4O8 under the electron beam

    International Nuclear Information System (INIS)

    Domenges, B.; Hervieu, M.; Raveau, B.; Karpinski, J.; Kaldis, E.; Rusiecki, S.

    1991-01-01

    The stability of the high oxygen-pressure 80K-superconductor YBa 2 Cu 4 O 8 under the electron beam was studied by high resolution electron microscopy. Several topotactic reductions were observed for which models are proposed. The most important feature deals with the topotactic transformation of YBa 2 Cu 4 O 8 into the 125-type phase Y 1+x Ba 2+2x Cu 5-3x O 9 (x = 0.14) involving order-disorder phenomena

  14. Anion Redox Chemistry in the Cobalt Free 3d Transition Metal Oxide Intercalation Electrode Li[Li0.2Ni0.2Mn0.6]O2.

    Science.gov (United States)

    Luo, Kun; Roberts, Matthew R; Guerrini, Niccoló; Tapia-Ruiz, Nuria; Hao, Rong; Massel, Felix; Pickup, David M; Ramos, Silvia; Liu, Yi-Sheng; Guo, Jinghua; Chadwick, Alan V; Duda, Laurent C; Bruce, Peter G

    2016-09-07

    Conventional intercalation cathodes for lithium batteries store charge in redox reactions associated with the transition metal cations, e.g., Mn(3+/4+) in LiMn2O4, and this limits the energy storage of Li-ion batteries. Compounds such as Li[Li0.2Ni0.2Mn0.6]O2 exhibit a capacity to store charge in excess of the transition metal redox reactions. The additional capacity occurs at and above 4.5 V versus Li(+)/Li. The capacity at 4.5 V is dominated by oxidation of the O(2-) anions accounting for ∼0.43 e(-)/formula unit, with an additional 0.06 e(-)/formula unit being associated with O loss from the lattice. In contrast, the capacity above 4.5 V is mainly O loss, ∼0.08 e(-)/formula. The O redox reaction involves the formation of localized hole states on O during charge, which are located on O coordinated by (Mn(4+)/Li(+)). The results have been obtained by combining operando electrochemical mass spec on (18)O labeled Li[Li0.2Ni0.2Mn0.6]O2 with XANES, soft X-ray spectroscopy, resonant inelastic X-ray spectroscopy, and Raman spectroscopy. Finally the general features of O redox are described with discussion about the role of comparatively ionic (less covalent) 3d metal-oxygen interaction on anion redox in lithium rich cathode materials.

  15. RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd). Syntheses of three new rare earth borates isotypic to Ce{sub 2}B{sub 8}O{sub 15}

    Energy Technology Data Exchange (ETDEWEB)

    Glaetzle, Matthias; Hoerder, Gregor J.; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

    2016-08-01

    The rare earth borates RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd) were synthesized in a Walker-type multianvil apparatus under conditions of 5.5 GPa and 1100 C. Starting from the corresponding rare earth oxides and boron oxide, the syntheses yielded crystalline products of all new compounds that allowed crystal structure analyses based on single-crystal X-ray diffraction data for La{sub 2}B{sub 8}O{sub 15} and Nd{sub 2}B{sub 8}O{sub 15}. The compound Pr{sub 2}B{sub 8}O{sub 15} could be characterized via X-ray powder diffractometry. The results show that the new compounds crystallize isotypically to Ce{sub 2}B{sub 8}O{sub 15} in the monoclinic space group P2/c. The infrared spectra of RE{sub 2}B{sub 8}O{sub 15} (RE = La, Pr, Nd) have also been studied.

  16. Twinning microstructure and charge ordering in the colossal magnetoresistive manganite Nd1/2Sr1/2MnO3

    International Nuclear Information System (INIS)

    Luo, Z.P.; Miller, D.J.; Mitchell, J.F.

    2000-01-01

    Charge ordering (C.O.) in the colossal magnetoresistive (CMR) manganites gives rise to an insulating, high-resistance state. This charge ordered state can be melted into a low-resistance metallic-like state by the application of magnetic field. Thus, the potential to attain high values of magnetoresistance with the application of small magnetic fields may be aided by a better understanding of the charge-ordering phenomenon. This study focused on microstructural characterization in Nd 1/2 Sr 1/2 MnO 3 . In Nd 1/2 Sr 1/2 MnO 3 , the nominal valence of Mn is 3.5+. On cooling, charge can localize and lead to a charge ordering between Mn 3+ and Mn 4+. The ordering of charge results in a superlattice structure and a reduction in symmetry. Thin foil specimens were prepared from bulk samples by conventional thinning and ion milling (at LiqN 2 temperature) methods. The room temperature TEM observation of Nd 1/2 Sr 1/2 MnO 3 reveals that it contains a highly twinned microstructure, together with a small number of stacking faults (SFS). A figure shows the same area of the specimen at different zone axes obtained by tilting around two perpendicular directions as indicated. Three grains A, B and C are labeled for each of the zone axes. The room temperature EDPs from the matrix and twins shows an approximate 90degree rotation suggesting a 90degree twin orientation. These results are further confirmed by C.O. at low temperatures. The twinning planes can be determined by tilting with large angles

  17. Hierarchically Structured Co3O4@Pt@MnO2 Nanowire Arrays for High-Performance Supercapacitors

    Science.gov (United States)

    Xia, Hui; Zhu, Dongdong; Luo, Zhentao; Yu, Yue; Shi, Xiaoqin; Yuan, Guoliang; Xie, Jianping

    2013-10-01

    Here we proposed a novel architectural design of a ternary MnO2-based electrode - a hierarchical Co3O4@Pt@MnO2 core-shell-shell structure, where the complemental features of the three key components (a well-defined Co3O4 nanowire array on the conductive Ti substrate, an ultrathin layer of small Pt nanoparticles, and a thin layer of MnO2 nanoflakes) are strategically combined into a single entity to synergize and construct a high-performance electrode for supercapacitors. Owing to the high conductivity of the well-defined Co3O4 nanowire arrays, in which the conductivity was further enhanced by a thin metal (Pt) coating layer, in combination with the large surface area provided by the small MnO2 nanoflakes, the as-fabricated Co3O4@Pt@MnO2 nanowire arrays have exhibited high specific capacitances, good rate capability, and excellent cycling stability. The architectural design demonstrated in this study provides a new approach to fabricate high-performance MnO2-based nanowire arrays for constructing next-generation supercapacitors.

  18. Magnetic properties of the compound Zn(Mnsub(0.98)Fesub(0.02)2O4

    International Nuclear Information System (INIS)

    Wautelet, M.; Gerard, A.

    1975-01-01

    Moessbauer spectra were measured of the compound Zn(Mnsub(0.98)Fesub(0.02)) 2 O 4 at several temperatures between 4.2 and 77 K. Evaluation of the spectra showed that the Neel temperature of ZnMn 2 O 4 does not exceed 50 K; the magnetic structure seems to be the same as that of Mn 3 O 4 with predominant B-B interactions. (A.K.)

  19. Oxidation of substituted alkyl radicals by IrCl62-, Fe(CN)63-, and MnO4- in aqueous solution. Electron transfer versus chlorine transfer from IrCl62-

    International Nuclear Information System (INIS)

    Steenken, S.; Neta, P.

    1982-01-01

    Alkyl radicals substituted at C/sub α/ by alkyl, carboxyl, hydroxyl, alkoxyl, and chlorine react in aqueous solutions with Ir/sup IV/Cl 6 2- to yield Ir(III) species. In the case of substitution by hydroxyl and alkoxyl, the rate constants are in the diffusion-controlled range ((4-6) x 10 9 M -1 s -1 ) and the reaction proceeds by electron transfer. In the case of ethyl, methyl, carboxymethyl, and chloromethyl radicals the rate constants range from 3.1 x 10 9 for ethyl to 2.8 x 10 7 M -1 s -1 for trichloromethyl and the reaction proceeds by chlorine transfer from IrCl 6 2- to the alkyl radical. With isopropyl and tert-butyll radicals the reaction proceeds by both electron and chlorine transfer. Alkyl radicals also react with Fe(CN) 6 3- . The rate constants increase strongly with increasing alkylation at C/sub α/ from 5 x 10 6 for methyl to 3.6 x 10 9 M -1 s -1 for tert-butyl, indicating that the transition state for the reaction is highly polar. Rate constants for reaction of MnO 4 - with alkyl radicals are of the order 10 9 M -1 s -1 . 4 figures, 1 table

  20. Nickel permanganate as a precursor in the synthesis of a NiMn2O4 spinel

    International Nuclear Information System (INIS)

    Schmidt, Jorge A.; Sagua, Aurora E.; Bazan, Julio C.; Prat, Maria R.; Braganza, Maria E.; Moran, Emilio

    2005-01-01

    The present study describes the preparation, characterization, and thermal decomposition of the compound Ni(MnO 4 ) 2 .xH 2 O, which was synthesized by a coprecipitation method at a low temperature. The role of this compound as a precursor in the synthesis of a Ni-Mn spinel was determined via X-ray, TG-DTA, electron diffraction, and EDAX measurements