The diffusion of Cd2 ions in KC1 crystals was studied at 350 to 500C by diffusion from radioactively tagged CdCl2 vapor. It was found that the diffusion coefficients of Cd could be expressed as functions of impurity concentration by means of the Lidiard equation for diffusion by impurity-vacancy complexes. The diffusion of the impurity-vacancy complexes as a function of temperature was given by:

D(cm2/s) = 4.68 x 10-5 exp[-12 400/RT]

F.J.Keneshea, W.J.Fredericks: Journal of Physics and Chemistry of Solids, 1965, 26[3], 501-8