IONIC ASSOCIATION OF SOME LITHIUM-SALTS IN 1,2-DIMETHOXYETHANE - A RAMAN-SPECTROSCOPIC AND CONDUCTIVITY STUDY

Precise measurements on electrical conductances as well as laser Raman spectra in the wavenumber range 3500-100 cm(-1) of five lithium salts in 1,2-dimethoxyethane (DME) have been reported. The conductance data are interpreted by the Fuoss-Kraus theory, yielding values for the io n-pair and triple-ion formation constants. The Raman spectra suggest t he presence of ''spectroscopically free'' ClO4-, BF4-, and AsF6-, ions in solutions, whereas there is no such evidence for either the Cl- or Br- ion, thus substantiating the very high ion-pair formation constan ts for LiCl and LiBr as obtained from conductance measurements. The ob served processes have been interpreted by an Eigen multistep mechanism . Changes in the Raman bands at ca. 867, 1147, 1452, and 2805 cm(-1) s uggest that the solvation of Li+ ion in DME occurs through the etherea l oxygen atom of the solvent molecule.