Tricaesium Ditellurium Tetravanadium Chloride Tetradecaoxide

The title compound, (CsCl)Cs₂(TeV₂O₇)₂, was obtained at 700 K during the crystallization of a mixed tellurium-caesium vanadate using tellurium tetrachloride as a transport agent. The structure consists of stacks of [V₂TeO₇] sheets alternately separated by layers of caesium atoms and layers of caesium and chlorine atoms. Within the sheets, the V atoms are distributed over two sites: a tetrahedral site containing V⁵⁺ ions and a square pyramidal site containing V⁴⁺ ions. The Te⁴⁺ ion lies within a tetrahedron formed by three O atoms and a lone pair. A maximum in the electron density is observed at the expected position of the lone pair.

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