A new type of mixed anionic framework in microporous caesium titanium vanadyl(V) phosphate Cs2[Ti(VO2)3(PO4)3]

A new compound—the first titanium vanadyl(V) phosphate Cs2[Ti(VO2)3(PO4)3]—has been obtained under hydrothermal conditions. Its crystal structure was determined by single crystal X-ray diffraction: space group P6ccP6cc, Z=4Z=4, a=13.765(1)a=13.765(1), c=9.4753(7) Åc=9.4753(7) Å at 293 K, wR2=0.068wR2=0.068, R=0.030R=0.030. In the structure [VO5] polyhedra form six-membered rings by sharing vertices. Each two neighboring V polyhedra in the ring are additionally bridged by [PO4] tetrahedra. All vanadyl groups (O6) remain terminal and are pointing toward the c  -direction giving rise to a strongly polar structure. Ti octahedra link these V, P rings by sharing all six vertices with P tetrahedra under formation of a three-dimensional anionic framework [Ti(VO2)3(PO4)3]2−∞∞∞. Intersecting channels in the [001], [100], [010], and [110] directions, containing the Cs cations suggest to consider the new compound as a possible 3D ion-conductor. Topological relations between this new structure and the mineral benitoit BaTiSi3O9 are discussed.

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