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 a=12.1230(2)Å, b=3.7168(1)Å, c=4.0336(1)Å, β=90.625(3)°β=90.625(3)° and Z=2Z=2 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.

View of the (a, c) and (a, b) planes (at left and right side, respectively) of the new vanadium molybdenum mixed oxide V1.1Mo0.9O5.Figure optionsDownload as PowerPoint slide