Model quasi-molecule Si2O as an approach in the IR spectra description glassy and crystalline framework silicates

Abstract

In MIR spectra of framework silicates, both in crystalline and glassy forms, three characteristic group of bands appear. These bands can be found in spectra of different compounds in almost the same wavenumbers range and having similar intensity rations. In this work new approach in the IR spectra description of framewoek silicates has been demonstrated. A bent quasi-molecule Si2O is used as a monomeric unit of structure. In model of Si2O unit three main bands in spectra are due to internal vibrations bridge SiOSi. There are stretching vibrations (1100–1100cm−1), bending (∼800cm−1) and rocking (∼470cm−1). Spectra obtained at low temperatures have been presented. Changes in spectra with decrease of temperatures contribute proposed model of quasi-molecule Si2O. A series of calculations and simulation of spectra has been also curried out. The study are based on the spectra of crystalline and glassy silica and potassium aluminosilicates.