Vibrational spectra of some glasses of alkali-metal nitrates with Group IIA and IIB metal nitrates and with zinc chloride and water

Abstract

Raman and infrared spectra are reported for mixed alkali metal–bivalent metal nitrate glasses, M¹NO₃–M²(NO₃)₂, with M¹ being Na, K, Rb, and Cs when M² is Mg, with M¹ being K and Rb when M² is Ca, with M² being K and Cs when M² is Zn, and with M¹ being Na, K, and Cs when M² is Cd. Spectra also are reported for mixed ZnCl₂–KNO₃ and ZnCl₂–CsNO₃ glasses, and for variably hydrated equimolar KNO₃–Mg(NO₃)₂ glasses. In each case the spectra show the presence in the glasses of nitrate groups strongly perturbed by association with the bivalent metal. The nature of this perturbation is analysed and its magnitude is shown to vary systematically with the constitution of the glasses. Low-frequency Raman lines given by the ZnCl₂-containing glasses are interpreted as showing the presence of polymeric species, which give way to simpler zinc–chloride–nitrate mixed complexes as the ZnCl₂ content is lowered.