Structure of vanadium tellurite glasses studied by neutron and X-ray diffraction

Details of the Te–O first-neighbor distances in V2O5–TeO2 glasses were obtained by neutron diffraction experiments with a measuring range up to Qmax=400 nm−1 (Q is the magnitude of scattering vector). A sharp Te–O peak at 0.191 nm and a second broad component at about 0.21 nm were resolved. Quantitative analyses of the areas of both peak components for a compositional series of four samples support the model of a change of TeO4 trigonal bipyramids to TeO3 trigonal pyramids upon V2O5 additions. In glasses of up to ∼10 mol% V2O5 each VOn polyhedron introduced is accompanied by the formation of a TeO3 unit. The number of TeO3 units increases further for glasses of higher V2O5 concentrations but the increase is less than that of the number of V sites.