Ga K-edge EXAFS analysis on the coordination of gallium in PbO–Ga 2O 3 glasses

Abstract

Ga K-edge extended X-ray absorption fine structure spectra of ( X)PbO–(1− X)Ga 2O 3 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 GaO 4 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 GaO 6 octahedra. The longer Ga–O bond distance in glasses compared to that in β-Ga 2O 3 crystal composed of similar GaO 4 tetrahedra indicated the presence of oxygens bonded to three independent cations.