Tantalum Chlorides in Octahedral Cluster Chemistry: The Structures of Cs2PbTa6Cl18 and CsPbTa6Cl18
| Autor: | Marcel Sergent, Stéphane Cordier, C. Loisel, Christiane Perrin |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Octahedral cluster
Stereochemistry Tantalum Stacking chemistry.chemical_element Electronic structure Crystal structure Condensed Matter Physics Electronic Optical and Magnetic Materials Inorganic Chemistry Crystallography chemistry Materials Chemistry Ceramics and Composites Molecule Density functional theory Physical and Theoretical Chemistry Valence electron |
| Zdroj: | Journal of Solid State Chemistry. 147:350-357 |
| ISSN: | 0022-4596 |
| DOI: | 10.1006/jssc.1999.8337 |
| Popis: | Two new series of Ta 6 chlorides, Cs 2 M ′ II Ta 6 Cl 18 and Cs M ′ II Ta 6 Cl 18 , have been isolated with M ′=Ba 2+ , Pb 2+ , Sr 2+ , Eu 2+ , Ca 2+ . From single-crystal structure refinements the compounds Cs 2 PbTa 6 Cl 18 [ R -3, Z =1, a =10.291(2) A, α =54.645(8)°] and CsPbTa 6 Cl 18 [ P -31 c , Z =2, a =9.2673(8) A, c =17.249(3) A] are isotypic with KLuNb 6 Cl 18 and CsLuNb 6 Cl 18 , respectively. In the former compound the structure consists of a fcc stacking of Ta 6 Cl 18 units, while a pseudohexagonal AA′A stacking of units is observed for the latter compound. The tetrahedral site of units, half-occupied by K + in KLuNb 6 Cl 18 is fully occupied by Cs + in Cs 2 PbTa 6 Cl 18 . The interatomic distances are consistent with valence electron concentrations per cluster (VEC) of 16 and 15 for Cs 2 PbTa 6 Cl 18 and CsPbTa 6 Cl 18 , respectively. It is the first time that such a VEC of 15 is observed for a quaternary Me 6 X 18 -unit based compound; this feature is discussed in relation to the density functional theory results previously reported on Me 6 X 18 ( Me =Nb, Ta; X =Cl, Br). |
| Databáze: | OpenAIRE |
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