Effect of an electric field on brucite dehydroxylation

The dehydroxylation of brucite has been investigated in electric fields up to 400 kV/m at T = 623 K. It is revealed that this reaction in the presence and absence of the field is a diffusion-controlled process, and its rate i s governed by the diffusion rate of "slow" protons (the O2- states) in the Mg(OH)(2) crystal structure. A decrease in the activation energy for diffus ion of these protons in an electric field can be explained by both the addi tional energy acquired by the proton upon its migration through a distance of about 10(3) A and a certain decrease in the potential barrier. It is sho wn that the found decrease in height of this barrier can be caused by the i onic polarization of the brucite lattice in an electric field whose effect on the barrier depends on the net dipole moment responsible for the generat ion of dipoles in the structural region of radius similar to 200 Angstrom. (C) 2000 MAIK "Nauka/Interperiodica".