Reorganization of surface layers of crystal hydrates in dehydration/rehydration experiments

Abstract

Detailed studies by optical microscopy of the dehydration and rehydration of cleavage faces of a number of crystal hydrates have shown that, if the reaction is reversible, upon rehydration of a previously dehydrated surface the texture of the surface under examination changes, either in a manner which is immediately evident (orange-peel formation) or in a more concealed way which can be revealed upon renewed dehydration (enhanced nucleation).

These findings, which are in agreement with a recent reconsideration of the nature and function of nuclei present in dehydration reactions, are considered to be a generalization of previous findings and indicate the need to revise the interpretation of nucleation reactions, at least in the case of reversible dehydration.