Changes in the IR Spectra of Aqueous Solutions of Alkali Metal Chlorides during Crystallization

Abstract

The IR spectra of aqueous solutions of sodium chloride and rubidium chloride with the same concentration of 0.1 M upon freezing are studied in the middle IR region. The changes that occur in the absorption bands of the bending ν₂, compound ν₂ + ν_L, and stretching (ν₁, 2ν₂, and ν₃) vibrations of water molecules with gradual crystallization of the solutions are studied. The obtained spectra of crystallized solutions are compared to the IR spectrum of ice Ih. Analysis allows conclusions about the structure of the investigated frozen crystallized solutions.