New Ways of Characterizing Layered Silicates and their Intercalates

Four new methods of probing the atomic and microstructural characteristics of the clay minerals are described: solid-state, magic-angle-spinning ²⁷Al and ²⁹Si n.m.r. (along with ¹³C n.m.r. of mobile, intercalated organic species); X-ray induced photoelectron studies encompassing photoelectron diffraction as a complement to conventional photoelectron spectroscopy; high-resolution electron microscopy either alone or in association with electron-stimulated X-ray emission microanalysis; and neutron scattering techniques. In reviewing the principles, scope and application of these methods specific case histories are selected from representative minerals belonging to the serpentines, kandites, smectites, micas, vermiculites, chloritoids, zeolites and intergrowths of these with one another or with other silicate minerals. Emphasis is placed on problems not readily amenable to solution by traditional, X-ray based procedures.