The interaction of nickel oxide with gaseous chlorine is studied from 200 t
o 850 degreesC. The formation of nickel chloride begins at 350 degreesC. Be
tween 400 and 700 degreesC, the process is accompanied by chlorine accumula
tion in the solid and is controlled by the growth of NiCl2 nuclei. The chlo
rination product, NiCl2, sublimes at temperatures above 750 degreesC. The r
ate-controlling stage of chlorination is sublimation.