Synthesis and crystal structure determination of three layered-type thiophosphate compounds KMP₂S₇ (M = Cr, V, In)

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• 作者：Kopnin ; E. ; Coste ; S. ; Jobic ; S. ; Evain ; M. ; Brec ; R.
• 关键词：A. Chalcogenides ; A. Layered compounds ; C. X-ray diffraction ; D. Crystal structure
• 刊名：Materials Research Bulletin
• 出版年：2000
• 出版时间：July 1, 2000
• 年：2000
• 卷：35
• 期：9
• 页码：1401-1410
• 全文大小：248 K

文摘

Three new thiophosphates KMP₂S₇ (M = Cr, V and In) have been synthesized and their structure determined from twinned crystals through X-ray diffraction experiments. The three compounds crystallize in the monoclinic system, space group C2 and Z = 2, with the following lattice parameters: KCrP₂S₇, a = 8.5146(6), b = 9.5848(6), c = 6.3052(5) Å, β = 97.981(8)°, V = 509.59(6) ų; KInP₂S₇, a = 8.7506(9),b = 9.9685(9), c = 6.3151(8) Å, β = 98.906(13)°, V = 544.2(2) ų; KVP₂S₇, a = 8.5553(6), b = 9.5765(5), c = 6.3323(4) Å, β = 98.630(8)°, V = 512.8(1) ų. For each compound, the structure determination was carried out taking into account the two twin domain sets (rejecting only the partially overlapping reflections) down to R = 3.08 % , R = 3.20 % , and R = 3.08 % (2σ level) for KCrP₂S₇, KInP₂S₇, and KVP₂S₇, respectively. The two-dimensional structures, built from bitetrahedral [P₂S₇] units sharing edges and corners with [MS₆] octahedra, are isotypic to the structure of RbVP₂S₇, with the same nonharmonic behavior of the alkali metal.