Ethylene glycol and glycerol complexes of smectites and vermiculites

Abstract

The complexes formed by ethylene glycol, HOCH₂.CH₂OH, and by glycerol, HOCH₂.CHOH.CH₂OH, with smectites (montmorillonite-saponite group), and vermiculites have received more attention than any other group of organo-silicate complexes. This interest arose in the first place from their use for identification purposes as proposed by MacEwan (1944, 1946) and by Bradley (1945b). Over the years, increasing attention has been given to the manner in which these complexes vary with the nature of the mineral, the magnitude and source of the charge on the silicate layers, and the number and kind of the exchangeable cations between the layers. The layer charge is determined most reliably from the full chemical analysis of a mineral, but more commonly is estimated from a measurement of cation exchange capacity.