It was recalled that it had recently been argued that halide tracer diffusion occurred via cation di-vacancies in AgBr at moderate temperatures, and at all temperatures in the case of AgCl. It was pointed out here that, in addition to some unanswered questions concerning the proposed mechanism, the experimental data which had been quoted in fact contradicted the model; rather than supporting it, as claimed.

A.P.Batra, L.Slifkin: Journal of the Physics and Chemistry of Solids, 1995, 56[1], 151-2