Glass-Transition Temperature, Electrical Conductance, Viscosity, Molar Volume, Refractive Index, and Proton Magnetic Resonance Study of Chlorozinc Complexation in the System ZnCl2 + LiCl + H2O

Several physicochemical techniques have been utilized to study mixed aqueous solutions of ZnCl2 and LiCl along selected pseudobinary composition lines in the concentration range from 2.8 to 22.2 m. Measurements of glass-transition temperature, electrical conductance, viscosity, molar volume, refractive index, and proton chemical shift indicate with varying sensitivity that the behavior of these electrolytes is dominated by chlorozinc complexation. The effects of complexation are most sensitively shown by the PMR spectra. In solutions containing more than 6 moles of water per mole of salt, it is probable that several complexation equilibria occur. When the water content is reduced to less than 6 moles per mole of salt, formation of tetrachlorozincate anions appears almost exclusively to be responsible for the composition variation of the physical properties of the solutions. ZnCl4= appears to be an even weaker base than -ClO4-.