STRUCTURAL STUDY OF WO3-TEO2 GLASSES

Raman spectra of WO3-TeO2 glasses and tungstate crystals were investigated. Properties of the glasses such as transition temperature, thermal expansion and density were measured. In the glasses, most tellurium atoms form TeO4 trigonal bipyramids and W=O bonds are present. The glasses contain clusters composed of corner-shared WO6 octahedra. An increase in WO3 content promotes the growth of clusters. The coordination state of W6+ having a W=O bond is discussed on the basis of crystal chemistry. Tungsten coordination polyhedra occupying the interface of the cluster have a W=O bond.