A gas-solid isotope exchange technique was used to study the diffusion of 36Cl in crystallites which had been prepared by reacting spectrographically pure Ni sponge with distilled HCl. The activation energy for Cl ion migration, at 180 to 340C, was found to be 1.01eV.

The Self-diffusion of Chloride Ions in Nickel Dichoride Crystallites and an Isotopic Exchange Reaction between Chlorine Gas and the Crystallites. Y.Sensui: Bulletin of the Chemical Society of Japan, 1972, 45[9], 2677-83