Iodous acid is the chemical compound with the formula HIO<sub>2</sub>. Its salts are named iodites; these are exceedingly unstable and have been observed but never isolated. They will rapidly disproportionate to molecular iodine and iodates.
Iodous acid is part of a series of oxyacids in which iodine can assume oxidation states of âÂÂ1, +1, +3, +5, or +7. A number of neutral iodine oxides are also known.