Interlayer bonding

These include hydrazine, dimethylsulfoxide (DMSO), formamide and some derivatives (N-methylformamide and dimethylformamide), acetamide and some derivatives, and pyridine N-oxide. Some salts such as potassium acetate also intercalate kaolinites. Once intercalated by one of these small molecules or salts, other molecules which normally do not directly intercalate kaolins can be introduced by replacement. Further, the exposure of the inner surfaces by intercalation gives one the opportunity to alter the interlayer bonding of the kaolin layers by chemical modification of the inner surfaces. 

According to Pearson (1972) the rhombohedral structure of these elements can be considered a distortion of a simple cubic structure in which the d2/d ratio would be 1. The decrease of the ratio on passing from As to Bi, and the corresponding relative increase of the strength of the X-X interlayer bond (passing from a coordination nearly 3, as for the 8 — eat rule, to a coordination closer to 6) can be related to an increasing metallic character. 

We may start from the mle which relates the increase in the coordination number to the increase in adjacent bond lengths. In a molecular lattice a distinction between intermolecular and intramolecular bonds is made. In a layer lattice, such as graphite an analogous distinction may be made between interlayer bonds and intralayer bonds. 

Jadoon, A.K., Ralph, B., and Hornsby, P.R., Metal to ceramic joining via a metallic interlayer bonding technique, J. Mater. Proc. Techn. 152 (2004) 257-265. 

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