Spectroscopic evidence for selenium(iv) dimerization in aqueous solution

Abstract

The aqueous speciation of selenium(IV) was elucidated by a combined approach applying quantum chemical calculations, infrared (IR), Raman, and ⁷⁷Se NMR spectroscopy. The dimerization of hydrogen selenite (HSeO₃⁻) was confirmed at concentrations above 10 mmol L⁻¹ by both IR and NMR spectroscopy. Quantum chemical calculations provided the assignment of vibrational bands observed to specific molecular modes of the (HSeO₃)₂²⁻ ion. The results presented will provide a better understanding of the chemistry of aqueous Se(IV) which is of particular interest for processes occurring at mineral/water interfaces.