Structural and dynamical properties of intercalated solids in general , and layered silicates of the type AxB1−x -Vermiculite in particular, are of both fundamental and practical interest. In these systems, two types of ions A and B with different ionic radii occupy the space between two silicate layers. On the fundamental side, one is interested in studying the average interlayer spacing as a function of (1) the concentration x of the large ion, (2) sizes and compressibilities of the intercalated ions and (3) the transverse rigidity of the silicate layers. In addition, one is interested in the dynamic properties of these solids. On the practical side, when the size difference between the two intercalants is large, one obtains pillared clays which are characterized by widely spaced silicate layers that are propped apart by sparsely distributed larger interlayer cations (sometimes referred to as pillars) . The enormous free volume of accessible interior space that is derived from such an open structure has significent practical application in the field of catalysis and sieving.