Thermal intercalation of alkali halides into kaolinite

Solid state intercalation of alkali halides into kaolinite takes place by h eating pressed disks of dimethylsulfoxide (DMSO)-kaolinite complex ground i n different alkali halides. This reaction involves diffusion of the DMSO ou tside the interlayer space and the alkali halide into the interlayer spate. IR and Raman spectroscopy reveal two types of intercalation complexes: (i) almost non-hydrous, obtained during thermal treatment of the DMSO complex; and (ii) hydrated, obtained by regrinding the disk in air. The strength of the hydrogen bonds between intercalated water or halide anions and the inn er surface hydroxyls decreases in the order Cl->Br->I-. Chlorides penetrate the ditrigonal holes and form hydrogen bonds with the inner OH groups.