Anion effect on the properties of some lithium salts in diethyl carbonate

A physicochemical study was made on solutions of a number of lithium salts in diethyl carbonate (DEC) within -20+60°C by means of isothermal saturation, densimetry, and conductometry. The solid phase composition in saturated solutions for LiBF₄, LiPF₆, and LiCIO₄ in DEC were determined. The solubility of the crystal solvates LiBF4·DEC and LiPF₆·2DEC increases with temperature while the temperature dependence of the LiCIO₄·2DEC goes through an extremum. The temperature solubility coefficient of LiCIO₄ (LiPF₆) is positive while that of LiBF₄ is negative. The density of each system under study is a linear function of both temperature and concentration. The conductivity of each system rises when the salt concentration varies from 0.25 to 2.25 M. The composition dependence of equivalent conductivity has an extremum, which is typical for systems of such a kind. At any temperature and concentration, the salts can be arrange according to their conductivity; PF₆^- > ClO₄^- > > BF₄^-.