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The Crystal Structure of Bi 8 (AlCl 4 ) 2 and the Crystal Structure, Conductivity, and Theoretical Band Structure of Bi 6 Cl 7 and Related Subvalent Bismuth Halides
Author(s) -
Beck Johannes,
Brendel Claus J.,
BengtssonKloo Lars,
Krebs Bernt,
Mummert Marita,
Stankowski Alexander,
Ulvenlund Stefen
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.19961291013
Subject(s) - bismuth , chemistry , crystal structure , crystallography , halide , anisotropy , conductivity , band gap , electronic band structure , cluster (spacecraft) , semiconductor , inorganic chemistry , condensed matter physics , materials science , physics , optoelectronics , organic chemistry , quantum mechanics , computer science , programming language
The methods of preparation for Bi 8 (AlCl 4 ) 2 and Bi 6 Cl 7 have been improved and the single crystal structures for these cluster compounds re‐investigated and re‐interpreted. In addition, conductivity measurements and band structure calculations using the tight‐binding approximation have been performed on Bi 6 Cl 7 and related subvalent bismuth halides. – Bi 8 (AlCl 4 ) 2 consists of isolated AlCl 4 ‐ anions and rather undistored square‐antiprismatic Bi 8 2+ clusters with an average Bi–Bi distance of 3.10 Å. Relatively short intercluster Bi–Bi contacts of 3.90 Å suggest weak bonding interactions between the Bi 8 2+ units. In contrast, the structure determination of Bi 6 Cl 7 implies that this structure should be regarded as being composed of discrete Bi 9 5+ clusters and a polymeric Bi III– Cl anionic lattice including infinite, distorted α 1 [Bi 2 Cl 2 4+ ] chains. According to the experimental and theoretical results, the Bi 6 X 7 (X = Cl, Br) family of subvalent bismuth halide compounds are anisotropic semiconductors along the crystallographic c axis. The conductivity is mediated by the onedimensional α 1 [Bi 2 Cl 2 4+ ] chains. These are interconnected with the Bi 9 5+ clusters, which are acting as electron reservoirs. The related BiX (X = Br, I) family of subvalent bismuth halides are shown to be anisotropic semiconductors in the crystallographic b direction.