TEMPERATURE STABIL IT IES OF MONTMORILLONITE- AND VERMICUL ITE-GLYCOL COMPLEXES 1 By

Stabilities of Mg-, Ca-, and Na-montmorillonite- and vermiculite-glycol complexes are compared by heating experiments with the oscillating-heating x-ray powder diffraction method. In the course of expulsion of glycol from the 17A two-layer glycol complexes of the Mg-, Ca-, and Na-montmorillonites, a 14A one-layer complex is encountered which is substantially the same as the 14A one-layer vermiculite-glycol mplex. One.dimensional Fourier methods are utilized for analysis of interlayer liquid distributions. Direct observations of x-ray diffraction phenomena under dynamic condi-tions during the course of dehydration of monoionic montmorillonites reported at the Fourth National Clay Minerals Conference (Rowland, Weiss, and Bradley, 1956) indicated a transient intermediate hydration stage of about ll.5A, from which surprisingly close approach of water molecules to complex silicate layers was inferred. The range of temperature of stability seemed too narrow for collecting data for analysis by Fourier methods, but two avenues of approach suggested them