OXYGEN COORDINATION OF MAGNESIUM AND CALCIUM IN BINARY MAGNESIA AND CALCIA META-PHOSPHATE GLASSES

An X-ray diffraction study has been carried out on binary phosphate and silicate glasses with MgO or CaO in equimolar composition. The structure of a 60 mol% CaO-40 mol% Al//2O//3 glass was also investigated for comparison. The electron radial distribution function was calculated by the Fourier transformation and the interpretation is made in terms of pair functions. The number of oxygens around magnesium is four in both phosphate and silicate glasses. The number of oxygens which surround calcium appears to depend on the component of network formers; the oxygen coordination numbers around calcium are five in phosphate, six in silicate and four in aluminate glasses, respectively.