“…The highest intensity ClO 4 – anion Raman ν 1 band, near 963 cm –1 in the LiClO 4 salt (Figure ) and near 933 cm –1 for the uncoordinated anion, is due to the Cl–O symmetric stretching vibration . This band is highly sensitive (i.e., band positional shift) to Li + cation coordination and many studies have examined this band to identify solvates in solution via the assignment of the band positions to the uncoordinated ClO 4 – anion and the anion coordinated to one or more Li + cations. − Unfortunately, as noted above, the Raman ν 2 , ν 3 and ν 4 bands due to symmetric stretching, antisymmetric stretching and antisymmetric deformation vibrations, respectively, do not permit the facile assignment of the Li + cation coordination modes since several bands are associated with these vibrations and the band positions tend to overlap with the bands for solvent molecules (see Supporting Information). In addition, chlorine isotopes have a natural abundance of 75.8% 35 Cl and 24.2% 37 Cl. , Two bands thus occur for each of the ClO 4 – vibrational modes in which the chlorine nucleus in displaced (i.e., the ν 3 and ν 4 bands) .…”