Vibrational spectra of alkali and alkaline earth metal complexes, oxide glasses and oxyanion salts

Abstract

Infrared and Raman Spectra of Li +, Na +, K + and Mg 2+ complexes of amides have been studied and assignments made of low frequency bands characteristic of metal—oxygen polyhedra (in the case of Li +, asymmetric stretching is around 400 cm −1). Infrared spectra of pyridine and CH 3CN complexes with characteristic MN bands are reported. Analysis of the spectra of linear O M +O ( M = H, D or Li) systems in sparteine-N 16-oxide sesquiperchlorate has established the D ∞ h symmetry of the group with the characteristic OLi +O asymmetric stretching mode around 400 cm −1. Crown ether complexes of Li + show characteristic LiO 4 bands around 400 cm −1. Crystalline oxides of Li with well-defined LiO 4 tetrahedra also exhibit the 400 cm −1 band due to LiO stretching. Oxide glasses show low frequency bands characteristic of the metal—oxygen polyhedra. These bands are shown to be useful in determining the nature of cation coordination in a variety of systems.