Effect of high polarizability on mobilities in tonic melts

The effect of cations having high polarizability on the mobilities of coexi sting cations as well as of the cations themselves has been studied for Ag, Tl+ and Cs+ ions. We have previously found that the internal mobilities, u, of alkali ions in molten salts such as nitrates are well expressed by an empirical equation:u = [A/(V-m-V-0)] exp(-E/RT), where V-m is the molar vo lume, and A, V-0 and E are parameters nearly independent of coexisting cati ons. In binary melts (M, Ag)NO3, u(M) except for M=Li+ becomes smaller than expressed by this equation; Ag+ ion has a tranquilization effect on u(M). On the contrary, in (M, Tl)NO3, u(M) becomes higher than according to the e quation, which means that Tl+ has an agitation effect on u(M). It is found that Cs+, having a high polarizability, also has an appreciable agitation e ffect.