Attribution of the OH stretching bands of kaolinite

Abstract

Abstract Examination of the infrared spectra of synthetic kaolinites, with various degrees of substitution of hydroxyls by OD groups, allows a more detailed attribution of the stretching bands due to inner-surface hydroxyls of kaolinite. Among the three innersurface OH groups of the unit cell, two are nearly perpendicular to the sheet and give coupled vibrations which are responsible for the bands around 3695 and 3670 cm −1 ; the band near 3655 cm −1 is due to the other hydroxyl, which is lying close to the sheet.