Molecular interactions in aqueous solutions of polyborates at different acidity based on the Raman spectroscopy data at 25°C

Abstract

Investigation of aqueous solutions of polyborates LiB(OH)₄, Li₂B₄O₅(OH)₄, and LiB₅O₆(OH)₄ at different acidity has been performed by Raman spectroscopy at 25°C. The geometries and Raman vibrational frequencies of H₃BO₃ in aqueous phase were calculated at different basis sets, and verified the veracity. The calculated characteristic Raman shifts of B(OH)₃, B(OH)₄⁻, B₃O₃(OH)₄⁻, B₃O₃(OH)₅²⁻, B₄O₅(OH)₄²⁻, and B₅O₆(OH)₄⁻ were assigned to 880.0, 735.33, 599.06, 740.16, 551.67, and 521.04 cm⁻¹, respectively. Assignments of the bands were tentatively ascribed by comparing the calculated Raman spectrum. The chemical species distribution and the relevant molecular interaction mechanisms in the polyborates solutions were suggested.