Electric conduction in molten salts

Molten additive binary systems having a common anion yield much more heuris tic information for a better understanding of the mechanism of ionic conduc tion than pure melts do. In most of such systems the Chemla effect occurs;t he mobility isotherms of two cations have a crossing point called the Cheml a crossing point. In binary multivalent cation systems, the larger cation i s more mobile than the smaller one. An internal mobility ri of a monovalent cation is generally expressed by an empirical equation: u= [A / (V-m-V-o)] exp(-E / RT), where V-m, is the molar volume;A, V-o and E are constants nea rly independent of the kind of the second cation. Deviation from this equat ion could be interpreted in terms of the agitation effect (positive deviati on), and the tranquilization effect or the free space effect (negative devi ation). The dynamic dissociation model well accounts for the above-mentione d findings;in other words, the internal mobility is strongly related to the dissociative motion of neighboring cation and anion. The effect of highly polarizable cations on internal mobilities is also discussed.