Acta Cryst. (2007). E63, i127-i128  [ doi:10.1107/S1600536807016790 ]

A synchrotron study of Ba₅Ta₂Cl₂O₉

A. D. J. Barnes, M. G. Francesconi and T. J. Prior

Abstract: The structure of pentabarium ditantalum dichloride nonaoxide, Ba₅Ta₂Cl₂O₉, is isotypic with Ba₅Ru_1.6W_0.4Cl₂O₉ and with one polymorph of Ba₅Ru₂Cl₂O₉. It is related to the perovskite structure and shows a ten-layer stacking of BaO₃ and BaCl blocks along the c axis. The Ta cations occupy octahedral interstices, forming Ta₂O₉ dimers of distorted face-shared TaO₆ octahedra. Except for one O atom, all atoms are situated on special positions: Ba1 (Wyckoff position m2), Ba2 and Ba3 (3m.), Ta (3m.), Cl (3m.) and O1 (mm2).

Online 20 April 2007

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