Distorted bcc Indium Cubes as Structural Motifs in Ca[TIn4] (T=Rh, Pd, Ir)
✍ Scribed by Rolf-Dieter Hoffmann; Rainer Pöttgen
- Book ID
- 101307189
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 185 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
The title compounds were prepared from the elements by reactions in water-cooled glassy carbon crucibles under an argon atmosphere in a highfrequency furnace. CaPdIn 4 crystallizes with the YNiAl 4 -type structure: Cmcm, a 446.7(3), b 1665(1), c 754.3(5) pm, wR2 0.0465 with 646 F 2 values and 24 variables. The structure is built up from a complex three-dimensional [PdIn 4 ] polyanion in which the calcium atoms occupy distorted pentagonal tubes formed by indium and palladium atoms. CaRhIn 4 and CaIrIn 4 adopt the LaCoAl 4 -type structure: Pmma, a 867.6(1), b 422.91(8), c 745.2(1) pm, wR2 0.0583 with 468 F 2 values and 24 variables for CaRhIn 4 ; a 869.5(1), b 424.11(6), c 746.4(1) pm, wR2 0.0614 471 F 2 values with 24 variables for CaIrIn 4 . This structure type, too, has a three-dimensional [RhIn 4 ] polyanion which is related to the structure of binary RhIn 3 . The calcium atoms fill distorted pentagonal prismatic channels formed by indium atoms. Semi-empirical band structure calculations for Ca-RhIn 4 and CaPdIn 4 reveal strongly bonding InÀIn, RhÀIn and PdÀIn interactions but weaker CaÀRh, CaÀPd and Ca À In interactions. CaRhIn 4 and Ca-PdIn 4 are compared with other indiumrich compounds such as YCoIn 5 and Y 2 CoIn 8 , and with elemental indium. Common structural motifs of the indium-rich compounds are distorted bcclike indium cubes.