An X-ray diffraction study of aqueous emulsions of a Na-montmorillonite shows that: (1) At low water content, the d-spacings of the montmorillonite increased stepwise with increasing water content; (2) At high water content, sharp (001) peaks due to regular stacking of montmorillonite layers were not detectable, but broad, halo patterns were observed in the low-angle scattering region; and (3) The addition of Ca2+ or H+ to the aqueous emulsions caused Ca-montmorillonite or H-montmorillonite crystals to form. A zig-zag column model of montmorillonite layers fits the observed data for aqueous emulsions of Na-montmorillonite.
