An empirical relation between the limiting ionic molar conductivities and self-diffusion coefficients of pure solvents

Abstract

The limiting ionic molar conductivity (λ∞) of an electrolyte solution depends on the self-diffusion coefficient (Ds) of the pure solvent when the temperature (T) changes. To study the Ds-dependence of λ∞, we proposed a new empirical relation λ∞∝(Ds/T)t, with a parameter t. The relation is applied to the λ∞ and Ds of alkali, tetra-alkyl ammonium, and halogen ions in water or methanol. All ions except for tetra-alkyl ammonium ions in water exhibit excellent linear relationships in their λ∞∝(Ds/T)tplots, with t in the range from 0.88 to 1.26. This is the first report showing an affirmative linear correlation between λ∞ and Ds.