On the new oxovanadium phosphate NaZnVOPO4(HPO4) obtained at 510 K from hydrothermal treatment

Pale blue powders of NaZnVOPO4(HPO4) were prepared in quantitative yield fr om hydrothermal treatments. The structure of NaZnVOPO4(HPO4) was solved fro m single crystal X-ray diffraction data in the centrosymmetric monoclinic s pace group P2(1/c) (no. 14), a = 8.5441(2) Angstrom, b = 8.9831(2) Angstrom , c = 9.0836(2) Angstrom, beta = 91.241(1)degrees, Z = 4 (R-1(F-o) = 0.026, wR(2)(F-o(2)) = 0.068). The structure results from the hetero-condensation of distorted octahedra VO6 with tetrahedra HxPO4 and ZnO4 by sharing apice s and edges. The remaining voids of the 3D framework [ZnVOPO4(HPO4)](-) loc ated in tunnels that run along [011] are occupied by sodium ions. The title compound dehydrates at T similar to 770 K with an overall weight loss of s imilar to2.3% consistent with the structural results. The crystal chemical relationships with Na3VOPO4(HPO4) and the high-temperature phase SrZnVO(PO4 )(2) are discussed.