Disordered structure of ZrW1.8V0.2O7.9from a combined X-ray and neutron powder diffraction study at 530 K

A novel compound, vanadium aliovalent substituted zirconium tungstate, ZrW1.8V0.2O7.9, was prepared with vanadium substituting tungsten rather than the common zirconium substitution. The structure of the high-temperature phase was refined from combined neutron and X-ray powder diffraction data gathered at 530 K. This phase is the disordered centric modification (space group Pa3) and the average crystal structure is similar to that of beta-ZrW2O8. The V atom occupies only a W2 site and charge compensation is achieved through oxygen vacancy, i.e. the oxygen vacancy occurs at only the O4 site. [Atom names follow the established scheme; Evans et al. (1996). Chem. Mater. 8, 2809-2823.].