Hypoiodites

Hypoiodites are chemical species containing the hypoiodite ion IO−, the anion of hypoiodous acid HOI. They belong to the hypohalite family, which also includes hypochlorite (ClO−) and hypobromite (BrO−). In aqueous solution, IO− is formed by deprotonation of HOI and represents iodine in the +1 oxidation state.

In solution, hypoiodite is relatively unstable and acts as a weak oxidizing agent. The iodate/iodide system is favored in many conditions, and IO− readily participates in redox chemistry. A characteristic reaction is the disproportionation of hypoiodite to iodate and iodide: 3 IO− → IO3− + 2 I−. This tendency toward disproportionation helps explain why hypoiodite species are typically transient and rarely isolated as stable solids.

Formation and stability: Hypoiodite is often produced in situ under basic or mildly oxidative conditions, or as an intermediate in iodine chemistry where HOI equilibrates with IO− in solution. Because IO− is prone to disproportionation, hypoiodite salts are not commonly stored or handled as stable, standalone compounds. When present, they exist mainly as aqueous solutions or transient intermediates rather than as robust solid reagents.

Reactions and applications: As oxidizing agents, hypoiodites can oxidize iodide further to iodate and can participate in various organic and inorganic oxidation processes. Compared with other hypohalites, hypoiodites are less stable and have fewer widespread practical applications. They are primarily of interest in fundamental iodine chemistry, analytical studies, and transient species investigations rather than in routine industrial uses.