Theoretical study of cation substitution in trioctahedral sheet of phyllosilicates.: An effect on inner OH group

The effect of substitutions of central cations in the octahedral sheet of trioctahedral phyllosilicates on the inner hydroxyl group was studied applying quantum-mechanical B3LYP/DZP method on cluster models of the solid. Changes of the geometry and of the stretching vibration of the inner hydroxyl group were observed. Calculated vibrational frequencies correlate with experimental spectra of 2:1 trioctahedral minerals of the talc type. The simulation of infrared spectra in the region of the stretching vibration of the inner OH groups was performed for several concentrations of the Ni2+ cation in the trioctahedral sheet. Simulated spectra are in good agreement with experimental ones of synthetic talc minerals containing different concentrations of the Ni2+ cation. (C) 2002 Published by Elsevier Science B.V.