Infra-red absorption of some solid silicates and phosphates with and without fluoride additions

Abstract

The infra-red spectra have been determined of rapidly cooled melts of sodium silicates and of the silico-phosphates of sodium and calcium, and also of the silicates of calcium, magnesium and barium prepared by solid-state reaction. The effects of fluoride additions on the spectra of the silicates of sodium and calcium and on calcium silico-phosphate have been examined. Displacement of the vi absorption peak to increasingly longer wavelengths with decreasing cation size, and the lifting of the triple degeneracy of the v3 absorption peak, have been observed. Absorption peaks due to the addition of fluoride have been assigned to silicon-fluorine bonding.