| Abstrakt: |
Tm5Pd4Ge8 was synthesized by melting of the elements in an arc-melting furnace. The new germanide was characterized by powder and single-crystal X-ray diffraction: own structure type, P21/m, a = 574.3(1), b = 1380.4(3), c = 836.4(1) pm, β = 107.57(2)°, V = 0.6321 nm3, wR2 = 0.0578, 2533 F2 values, 86 variables. The palladium and germanium atoms built up a three-dimensional [Pd4Ge8]15- polyanionic network which contains a unique germanium substructure composed of the Zintl anions Ge26- dumb-bells and Ge410- chains in cis-conformation. The palladium atoms within the network have distorted square pyramidal germanium coordination. The three crystallographically independent thulium atoms have coordination numbers 15, 16 and 17 with partial motifs of the Frank-Kasper type polyhedra. The isotypic germanide Er5Pd4Ge8 forms only after annealing the arc-melted sample at 1070 K for 1 week: a = 575.14(9), b = 1386.3(3), c = 838.4(1) pm, β = 107.51(2)°, V = 0.6375 nm³. [ABSTRACT FROM AUTHOR] |
