Electrical conductivity and ionic association of lithium and sodium perchlorates in tetrahydrofuran

Abstract

The total limiting molar electrical conductivities of ions and triads of ions and the association constants of ions with the formation of ion pairs and triads of ions were calculated from the concentration dependences of the electrical conductivity of solutions of lithium and sodium perchlorates in tetrahydrofuran at 278.15–318.15 K with the use of the method specially developed earlier. The experimental total limiting electrical conductivities were used to calculate the limiting molar electrical conductivities and attraction friction factors of separate ions (Li+, Na+, ClO 4 − , Li2ClO 4 + , Na2ClO 4 + , Li(ClO4) 2 − , and Na(ClO4) 2 − ). The constants of ion association into ion pairs were used to calculate the Gibbs energy of non-Coulomb interionic interaction (ΔG*+−), and the constants of association into triads of ions, to determine the a 3 distance parameter between the centers of the ion and the dipole of the ion pair. Positive ΔG*+−), values and deviations of the experimental a 3 value from the distance parameter calculated theoretically (a 3 0 ) for the triad of ions (Δa 3 = a 3 − a 3 0 ) were related to non-Coulomb repulsion in the region of overlap of the solvation shells of ions and the influence of temperature and ion charge density on this repulsion.