Acta Cryst. (2014). E70, i20
[ doi:10.1107/S1600536814007831 ]
Abstract: The title compound, nonaniobium vanadium pentacosaoxide, was prepared by a solid-state reaction at 1198 K. It is isotypic with Nb9AsO25, Nb9PO25 and Ta9VO25. The structure consists of NbO6 octahedra (one with 4/m.. and two with m.. symmetry) and VO4 tetrahedra (-4.. symmetry) sharing corners and edges to form a three-dimensional framework. This framework can be considered as a junction between ribbons made up from NbO6 octahedra and chains of NbO6 octahedra and chains of VO4 tetrahedra. The V site shows half-occupancy, hence one half of the VO4 tetrahedra is unoccupied. The structural differences with -Nb9VO25, VOSO4, SbOPO4 and NbOPO4 oxides are discussed.
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