An X-ray and neutron scattering study of the structure of zinc vanadate glasses

The short-range order of vitreous V₂O₅ and of three (ZnO)_x(V₂O₅)^1-x glasses with x = 0.2, 0.4, and 0.5 is studied by X-ray and neutron diffraction experiments where the change of the contrast allows to resolve the V-O and Zn-O correlations. The V-O and the Zn-O first-neighbor peaks are approximated by several Gaussian functions. In case of vitreous V₂O₅ two obvious V-O distances exist which are related with VO₄ and VO₅ units. With ZnO additions the V-O coordination number decreases from 4.4 in vitreous V₂O₅ to 4.0 in the metavanadate glass where the strongest decrease of the fraction of VO₅ units is found for glasses of x < 0.2. Dominantly, the VO₅ groups are linked with the neighboring units by corners. The Zn-O coordination numbers of the modified glasses are about five with closest distances of ≅ 0.200 nm.