INFRARED AND FOURIER-TRANSFORM RAMAN-SPECTROSCOPIC STUDY OF LITHIUM TRIFLUOROMETHANESULFONATE SOLUTIONS IN ACRYLONITRILE

Solutions of lithium trifluoromethanesulphonate (lithium triflate) in acrylonitrile (propenenitrile), in a range of concentrations between 0 .37 and 2.07 mol dm(-3) have been analysed by infrared (dispersive) an d FT-Raman spectroscopy. The new band in the v(C=N) region arising fro m the coordinated species Li+...(acrilonitrile)(n), has been examined in derail. A solvation number of three (at infinite dilution) was obta ined from the results of both techniques. This solvation number dimini shes with increasing salt concentration as a result of the ionic pairi ng. The data obtained in the analysis of the triflate anion v(4) (SO3 symmetric stretch) and v(10) (SO3 antisymmetric stretch) IR bands, ind icates the presence of two different species of ionic pairs. The stoic hiometry and structure of these ionic pairs are discussed.