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Two‐Dimensional [TIn 2 ] Polyanions in BaTIn 2 (T=Rh, Pd, Ir, Pt)—The Collapse of the Three‐Dimensional Indium Polyanion of BaIn 2
Author(s) -
Hoffmann RolfDieter,
Pöttgen Rainer
Publication year - 2001
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20010119)7:2<382::aid-chem382>3.0.co;2-i
Subject(s) - indium , tantalum , substructure , rhodium , crystallography , transition metal , materials science , single crystal , platinum , metal , hexagonal crystal system , diffraction , chemistry , metallurgy , catalysis , physics , optics , biochemistry , structural engineering , engineering
The title compounds were prepared from the elements by reactions in sealed tantalum tubes in a high‐frequency furnace. The four compounds were investigated by X‐ray diffraction both on powders and single crystals, and the structures of the rhodium and platinum compounds were refined from single‐crystal data: Cmcm, a =447.68(8), b =1131.1(2), c =805.6(2) pm, wR 2=0.0561, 354 F 2 values for BaRhIn 2 ; a =452.06(8), b =1162.4(2), c =801.5(1) pm, wR 2=0.1427, 362 F 2 values, for BaPtIn 2 : with 16 variables for each refinement. The structures are isopointal to MgCuAl 2 and can be considered to be a transition metal (T) filled CaIn 2 type, in which the indium atoms form a distorted network like hexagonal diamond (lonsdaleite). The indium substructure is cut apart in BaTIn 2 and resembles together with the transition metal atoms a two‐dimensional polyanion rather than a three‐dimensional polyanion as found in the compounds CaTIn 2 , CaTSn 2 , and SrTIn 2 . Semiempirical band structure calculations support the assumption of a two‐dimensional polyanion in which the strongest interactions are found for the T−In contacts.