Electrical conductances for some tetraalkylammonium bromides, lithium tetrafluoroborate and tetrabutylammonium tetrabutylborate in propylene carbonate at 25 °C

Abstract

Conductance measurements are reported for several symmetrical tetraalkylammonium bromides, lithium tetrafluoroborate (LiBF₄) and tetrabutylammonium tetrabutylborate (Bu₄NBBu₄) in propylene carbonate (PC) at 25 °C. The data have been analysed by the 1978 Fuoss conductance equation in terms of the limiting molar conductivity, Λ^o, the association constant, K_A, and the association distance R. The single-ion conductances have been determined from the Λ^o value of Bu₄NBBu₄ using it as a ‘reference electrolyte’. The results indicate that with the exception of LiBF₄ to some extent, other salts are almost unassociated in this solvent medium. The evaluation of Stokes radii of the ions indicate that Li⁺ is extensively solvated while the other ions remain almost unsolvated. The results have been discussed in terms of the ion-solvating ability of PC and also compared with the previous values in this system.