Abstract: 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 complex. One-dimensional Fourier methods are utilized for analysis of interlayer liquid distributions.