INFRARED STUDY OF THE OH GROUPS IN EXPANDED KAOLINITE.

Expansion of kaolinite with potassium acetate and with hydrazine followed by deuteration, shifts the absorption frequency at 3695 cm(-1) to lower values, but does not aflect the intensity of the 3620-cm(-1) absorption band. The band at 3695 cm(-1) is correlated predominantly to inner-surface hydroxyls with the dipole at right angles to the basal plane and the band at 3620 cm(-1) is related to inner hydroxyls with the dipole inclined toward empty octahedral sites.