Alumino-Silicate Clays and Clay Intercalation Compounds

Abstract

Intercalation compounds formed from graphitic host materials and from layer dichalcogenides such as TaS₂ and HfSe₂ are quite familiar to most solid-state physicists and chemists who have extensively studied the properties of such materials over the past several decades [1,2]. There is, however, another general class of host materials which can form a wide range of intercalation compounds yet has until very recently received very little attention from the solid-state community, although this class is heavily studied by inorganic chemists, soil scientists, geologists, and minerologists. This “new” class of materials is that which includes alumino-silicate clays (often called sheet silicate clays) [3–5]. Although the term “clay” is often used to refer to minerals, the morphology of which is small particles of a typical size less than 1μm, I will use the term in this paper as synonymous with layered alumino-silicates. In this chapter, I will clarify the relationship between layered alumino-silicates and the more familiar layered solids and, in addition, highlight the key features of the former which make them interesting systems for the exploration of unusual physical phenomena.