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

Infrared and Raman Spectra of Li+, Na+, K+ and Mg2+ 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 CH3CN 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-N16-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 LiO4 bands around 400 cm−1. Crystalline oxides of Li with well-defined LiO4 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.