Sample records for EUROPIUM 167 (europium 167)
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1

Polymorphism of Eu8In3 and the Solid Solution (CaxEu1 x)8In3c (No. 167), a = 957.7(1) pm, c = 5674(1) pm, Z = 12, R(F) = 0.020, wR(F2) = 0.038), the high temperature phase triclinic (P$\bar1$ (No. 2), a = 992.67(6) pm, b = 998.08(4) pm, c = 1007.89(5) pm, = 99.140(4) , = 101.172(5) , = 119.452(6) , Z = 2, R(F) = 0.035, wR(F2) = 0.080) in the Ca8In3 structure type. The densities ( triclinic = 6.36 g cm 1; trigonal = 6.90 g cm 1) as well as the synthesis conditions are compatible with the assignment as high and low temperature phase. The two polymorphs can be rationalized as polytypes of close packings of In with occupation of all octahedral holes and 5/6 of the tetrahedral voids. In this description, indium atoms realize the motif of a double hexagonal stacking for the low temperature modification and a cubic stacking for the high temperature phase. Alternatively, both structures can be described by the occurring coordination polyhedra (tetrahedra for europium, cubes, icosahedra and cubicosahedra surrounding indium). Eu8In3 is versatile to europium substitution by calcium, with little preference for either europium or calcium on the sites exhibiting the highest degree of distortion from tetrahedral shape (Ca4Eu4In3: P$\bar1$, a = 975.2(2) pm, b = 987.1(2) pm, c = 992.8(2) pm, = 99.12(3) , = 101.06(3) , = 119.59(3) , Z = 2, R(F) = 0.023, wR(F2) = 0.044). Dedicated to Professor Bernd Harbrecht on the Occasion of His 60th Birthday


2010-01-01

German National Library of Science and Technology (GetInfo) (German)