Layer rigidity in lamellar solids

A number of theoretical models have been put forth to account for the layer rigidity of a variety or intercalated layered solids with fixed host struc tures as revealed by the composition-dependence of die basal spacing. The m ain features of each model will be reviewed briefly and their strengths and weaknesses will be assessed. It will be shown that no single model propose d to date is sufficiently universal to explain the available data.