Hydrothermal synthesis and structure determination of the new vanadium molybdenum mixed oxide V1.1Mo0.9O5 from synchrotron X-ray powder diffraction data

A new vanadium molybdenum mixed oxide V1.1Mo0.9O5 [V(V)0.2V(IV)0.9Mo(VI)0.9O5] has been synthesized, as a pure phase, via hydrothermal methods in the presence of molybdic acid and vanadyl sulfate. Its crystal structure has been solved ab initio from high-resolution powder diffraction data collected at the ESRF beamline ID31. This compound crystallizes in the monoclinic symmetry, space group C2/m, with cell dimensions image, image, image, image and image per formula. The structure consists of double strings of VO5 square pyramids sharing edges and corners along [100] and [010], and more weakly bound along [001]. In this latter direction, the bond (V,Mo)–O=2.377 Å, while remaining long, leads for the first time to the interpenetration of the apical oxygens of the [(V,Mo)2O5]n layers, resulting in a three-dimensional (3D) structure closely related to R-Nb2O5. This structure will be compared to the pure layer structure of V2O5 where this bond reaches 2.793 Å.