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Crystal Structures and Preparation of K 2 AgVS 4 and Rb 2 AgVS 4 by Using the Molten Flux Method: Low‐Dimensional Materials with Infinite Metal‐Ion‐Centered Tetrahedra Chains
Author(s) -
Bensch Wolfgang,
Dürichen Peter
Publication year - 1996
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19961291011
Subject(s) - chemistry , tetrahedron , crystallography , ionic radius , ionic bonding , crystal structure , covalent bond , ion , organic chemistry
The quaternary sulfides K 2 AgVS 4 and Rb 2 AgVS 4 crystallize as dark violet needle‐like crystals with a metallic lustre. Infinite Ag‐ and V‐centered tetrahedra sharing common edges are running parallel to the crystallographic a axis. The chains are separated by K + or Rb + ions which are in an eightfold environment. The tetrahedra are occupied in an ordered fashion. The Ag–V interatomic distances amount to 2.904(1) and 2.910(1) A, respectively, which is significantly larger than the sum of the ionic radii of Ag + and V 5+ . Whereas the V–S distances are in the normal range, the average (Ag–S) distances are the shortest reported so far indicating strong covalent bonding between monovalent Ag + and S 2– . In addition, the title compounds represent very rare examples of AgS 4 polyhedra with equidistant Ag–S bonds. The geometrical parameters within the tetrahedra chains are only slightly affected when K + is replaced by the larger Rb + demonstrating the rigidity of the bonding properties within the tetrahedra. The compounds are isotypic with the quaternary copper sulfide K 2 CuVS 4 and the selenides K 2 CuMSe 4 (M=Nb, Ta).