Unit-Cell Dimensions of Two-Dimensionai Clay Minerals

Abstract The unit cell dimensions of minerals in the smectite group, regular and random mixed-layer groups, and halloysite shown in the Mineral Powder Diffraction File (1986) have been refined by least-squares analysis in the hexagonal system with a primitive lattice with indices restricted to hk or 00 l reflections. Trioctahedral minerals have larger a unit-cell dimensions than dioctahedral minerals.