Electrical Conductances for Tetraalkylammonium Bromides, LiBF4 and LiAsF6 in Tetrahydrofuran at 25°

Department of Chemistry, North Bengal University. Darjeeling-734 430 Manuscript received 23 December 1992 Electrical conductance data have been reported for tetraalkylammonium bromides, R4NBr (R = butyl to heptyl), lithium tetrafluoroborate (LiBF4) and lithium hexafluoroarsenate (LiAsF6) in tetrahydrofuran (THF) at 25°. Analysis of data by the Fuoss-Kraus theory of conductance reveals the presence of both ion-pairs and triple ions. The ion-pair (Kp) and triple-ion (KT) formation constants of these salts in tetrahydrofuran (THF) have been compared with the values obtained in 1,2-dimethoxyethane (1,2-DME). The comparison shows that the lower homologues of the studied R4NBr salts are more associated in THF than in 1,2-DME whereas the KT values in majority cases are much higher in 1,2-DME than in THF with the exception of LiAsF6. The results have been explained with the help of configurational entropy and molecular model theory