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) gl asses with x = 0.2, 0.4, and 0.5 is studied by X-ray and neutron diffractio n experiments where the change of the contrast allows to resolve the V-O an d Zn-O correlations. The V-O and the Zn-O first-neighbor peaks are approxim ated 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 additi ons 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 V O5 units is found for glasses of x < 0.2. Dominantly, the VO5 groups are li nked with the neighboring units by corners. The Zn-O coordination numbers o f the modified glasses are about five with closest distances of congruent t o 0.200 nm.