An Original Series in the Tantalum Cluster Oxohalide Chemistry with Isolated (Ta6Br15O3)5- Units: Crystal Structure of Cs2LaTa6Br15O3
✍ Scribed by S. Cordier; C. Perrin; M. Sergent
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 277 KB
- Volume
- 120
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
A new ternary oxobromide series, (M_{2} R E \operatorname{Ta}{6} \mathrm{Br}{15} \mathrm{O}{3}(M=) monovalent cation, (R E=) rare earth) based on (\left(\mathrm{Ta}{6} \mathrm{Br}{15} \mathrm{O}{3}\right)^{5-}) units, for which the valency electron count (VEC) is 14, has been isolated by solid state chemistry. The crystal structure of (\mathrm{Cs}{2} \mathrm{LaTa}{6} \mathrm{Br}{15} \mathrm{O}{3}), which crystallizes in the (\mathrm{P} \overline{3} 1 c) space group ( (a=9.512(2) \AA) and (c=17.935(3) \AA) ), has been refined from single crystal X-ray diffraction data. This structure is strongly related to the structure of (\mathrm{CsErTa}{6} \mathrm{Br}{88}) with a shift of the units along the (c) axis, which allows the building of new cationic sites. The developed formula of this compound is (M_{2} R E\left[\left(\mathrm{Ta}{6} \mathrm{Br}{9}^{i} \mathrm{O}{3}^{i}\right) \mathrm{Br}{6}^{r}\right]). The lanthanum is located in an original environment formed by three (\mathrm{O}^{i}) and six (\mathrm{Br}^{a}) belonging to three adjacent units, and the cesium is 12-coordinated in a complex site formed by six (\mathrm{Br}^{i}) and six (\mathrm{Br}^{a}) belonging to six adjacent units. Short distances between rare earths and (\mathbf{T a}_{6}) clusters are encountered. (1995 Academic Press, Inc.