Iodine chemistry in the +1 oxidation state. II. A Raman and uv–visible spectroscopic study of the disproportionation of hypoiodite in basic solutions

Abstract

The kinetics of disproportionation of elemental iodine to iodide and iodate ions has been studied in basic aqueous media using Raman and uv–visible spectroscopy. The IO stretching vibrations for IO − and I 2 OH − were observed at 430 ± 2 and 560 ± 2 cm −1 , respectively. The totally symmetric stretching vibration for [Formula: see text] was observed at 685 ± 2 cm −1 . The Raman results indicate that I 2 OH − is a linear molecule with a stronger I—O bond than IO − . The rate expression at 25 °C in 1 mol dm −3 NaOH was found to be[Formula: see text]where[Formula: see text]The reaction is primarily a reaction of the iodine +1 oxidation-state species IO − and I 2 OH − . It proceeds through the +3 oxidation-state species [Formula: see text] The following equilibrium and rate constants were determined:[Formula: see text]