Ga K-edge EXAFS analysis on the coordination of gallium in PbO-Ga2O3 glasses

Ga K-edge extended X-ray absorption fine structure spectra of(X)PbO-(1 - X)Ga2O3 glasses, where X is 0.7, 0.75 and 0.80 in mole fraction were recorded at room temperature to understand the coordination scheme of gallium in glasses. Analyses of the spectra indicate that most of the gallium forms GaO4 tetrahedra at the Ga-O bond distance between 0.1856 and 0.1861 nm with a negligible amount (less than 5% of total Ga-polyhedra) of GaO6 octahedra. The longer Ga-O bond distance in glasses compared to that in beta-Ga2O3 crystal composed of similar GaO4 tetrahedra indicated the presence of oxygens bonded to three independent cations. (C) 1997 Elsevier Science B.V.