| Popis: |
Ag0.37Crr21S2, rhombohedral, R3m, a = 3.4325 (1), c =- 37.190 (1) A (in hexagonal setting), Z = 6. The structure was determinined using singlecrystalX-ray data from 908 independent reflections; the least-squares refinement of the positional and thermal parameters and the population parameters ofAg and Cr led to a final R e = 0.102. It is a layer compound with hexagonal layers of atoms. Layers of S form a close packing of the type (hcch) 3, forming CrS 2 sandwiches with Cr in octahedral coordination. The gaps between these sandwiches are alternately occupied by Cr (2 x 0.21 Cr per site), also in octahedral coordination, and by Ag in tetrahedral holes. Both tetrahedral holes are partly occupied by 0.37 Ag; Ag is distributed over several sites within the S tetrahedra. |
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