Electrical conductance : density and viscosity studies of some alkali chloride-zinc melts

The binary MC1-ZnCl\\(_2\\) systems have been investigated by the following methods: density (M = Li, Na, K2 Cs), electrical conductance (M = Na, K, Cs), viscosity (M = Na). Measurements have been made from the liquidus to 600° and from pure ZnCl\\(_2\\) up to 0.6 mole fraction MC1. The applicability of the free volume, configurational entropy and hole models to the results is considered. It is found that the data are equally well represented by either of the first two models and that the predictions of the hole model are in agreement with experiment for mixtures containing more than 0.6 mole fraction MC1. The effects of the alkali chloride on the ZnCl\\(_2\\) structure are considered. It is concluded that the transport and density data are consistent with the breakdown of the network structure of ZnCl\\(_2\\) by the alkali metal chloride to give complex ions. From the experimental point of view, particular attention has been paid to the frequency dependence of conductance. It is concluded that the observed frequency dependence of 0.1% from 0.5 - 100 KHz is due to the error when the cell is balanced by a parallel combination of resistance and capacitance.