Acta Cryst. (2006). E62, i26-i28  [ doi:10.1107/S1600536805039723 ]

Tl₄Nb₂Se₁₁

C. L. Teske and W. Bensch

Abstract: The ternary compound tetrathallium diniobium undecaselenide, Tl₄Nb₂Se₁₁, was prepared by a molten flux method from a melt of Tl₂Se, elemental Se and Nb. The structure is composed of discrete Tl⁺ cations and complex [Nb₂Se₁₁]^4- anions. In the anion, the two crystallographically independent Nb atoms are sevenfold coordinated by Se atoms to form a distorted pentagonal bipyramid. Two NbSe₇ polyhedra have a face in common, thus yielding the [Nb₂Se₁₁]^4- unit. The crystal structure of Tl₄Nb₂Se₁₁ is isotypic with the structure of the homologous tantalum compound Tl₄Ta₂Se₁₁ [Teske et al. (2002). Z. Anorg. Allg. Chem. 628, 2651-2655], which was the first polyselenide with discrete complex [M₂Se₁₁]^4- anions.

Online 11 January 2006

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