Raman spectra of aqueous lithium salt solutions (LiCl, LiBr, and LiClO4) were measured from saturation concentrations to more dilute solutions at room temperature. In the saturated LiCl and LiBr solutions a polarized band at 380 and 335 cm(-1), respectively, was detected. This band was assigned to a symmetric vibrational mode from an inner sphere complex LiCl/Br(OH2)(n)(+) where n is probably three. In more dilute aqueous LiCl and LiBr solutions the high frequency component disappeared, and a new polarized band at 255 cm(-1) (FWHH 60 cm(-1)) was observed and assigned to the Li-O symmetric stretching motion of Li-(OH2)(4)(+). This is the first definitive report of the symmetric stretching motion of an univalent cation. Ab initio geometry optimizations and frequency calculations at the 3-21G and 6-31G* level were performed on the tetraaquolithium species and support our assignment.