Water layers in 2D frameworks

Two-dimensional lattices are particularly favourable for the formation of protonated water layers which can interact to varying extents with the supporting lattice. Clays are among the best known examples. Numerous compounds which can be prepared in the colloidal state show similar properties. Some materials are real ionic exchangers and can accommodate between their layers large quantities of various species such as hydrated or non-hydrated ions, polyfunctional organic molecules, solvents and other molecules. 

The hydrous layer silicates commonly known as clay minerals belong to the large family of phyllosilicates. The layer silicates contain continuous two-dimensional tetrahedral sheets in which tetrahedra are linked to form 

When clay minerals are treated with dilute acids ( activation process), protons may attack the silicate layers via the interlayer region and exposed edges. Octahedral ions such as AP and Mg are extracted into the interlayer which promotes a rapid decomposition. However, many mont-morillonites resist such a treatment, even when using concentrated acids . Formation of layer defects allows the number of anchoring points for new cations at the surface layer to increase. 

Room temperature conductivity of Na, Ca, Li and protonated clays varies from 10 to cm as a function of water content .  

Attempts to distinguish the contribution of solid clay particles and of 

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