Crystal structure features of the mixed-valence tellurium β-pyrochlores: CsTe1.625W0.375O6 and RbTe1.5W0.5O6

Abstract Two new isostructural mixed-valence tellurium oxides, CsTe1.625W0.375O6 (1) and RbTe1.5W0.5O6 (2), have been synthesized by solid-state reaction. The single crystals of obtained compounds have been characterized by single-crystal X-ray diffraction analysis. Both compounds have β-pyrochlore-type structure (cubic system, space group Fd-3m, Z ​= ​8) and the following unit cell parameters: a ​= ​10.5437(2) A in (1) and a ​= ​10.3949(3) A in (2). The structural features have been investigated, and the distortions of the building blocks [MO6] (M ​= ​Te, W) have been found. The oxidation states of tellurium have been confirmed by X-ray photoelectron spectroscopy. The thermal behavior of obtained compounds has been studied.