ChemInform Abstract: Study of Phase Transformation in BaTe₂O₆ by in situ High‐Pressure X‐Ray Diffraction, Raman Spectroscopy, and First‐Principles Calculations.

Abstract

The title compound is synthesized by solid state reaction of a stoichiometric mixture of BaCO 3 and TeO2 (air, 550 C for 6 h, and 650 C for 12 h). The product is characterized by in situ synchrotron powder XRD up to 16 GPa, Raman spectroscopy up to 37 GPa, and DFT calculations. At ambient conditions, BaTe 2O6 crystallizes in the orthorhombic space group Cmcm with Z = 4. The structure contains layers of [Te 2O6] 2units formed by TeO6 octahedra and TeO5 square pyramids. Around 10 GPa, a reversible structural transition occurs from orthorhombic to a monoclinic structure with space group P12 1/n and Z = 2. The transformation is accompanied by a slight rearrangement of the structural units. -(MISHRA*, K. K.; ACHARY, S. N.; CHANDRA, S.; RAVINDRAN, T. R.; PANDEY, K. K.; TYAGI, A. K.; SHARMA, S. M.; Inorg. Chem. 55 (2016) 1, 227-238, http://dx.