Iodine monoxide

This article is about the compound IO. For the oxoanion with the formula IO⁻, see hypoiodite. For the molecule I₂O, see Diiodine monoxide.

Iodine monoxide is a binary inorganic compound of iodine and oxygen with the chemical formula IO•. A free radical, this compound is the simplest of many iodine oxides.^[1][2][3] It is similar to the oxygen monofluoride, chlorine monoxide and bromine monoxide radicals.

Iodine monoxide

Names
Other names Iodine(II) oxide, iodosyl, oxidoiodine
Identifiers
CAS Number	14696-98-1 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:29896
ChemSpider	4574060
Gmelin Reference	1170
PubChem CID	5460557
CompTox Dashboard (EPA)	101316449
InChI InChI=1S/IO/c1-2 Key: AFSVSXMRDKPOEW-UHFFFAOYSA-N
SMILES [O]I
Properties
Chemical formula	IO
Molar mass	142.903 g·mol−1
Appearance	purple gas[citation needed]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

Iodine monoxide can be obtained by the reaction between iodine and oxygen:^[4]

I₂ + O₂ → 2 IO

Chemical properties

Iodine monoxide decomposes to its prime elements:^{[citation needed]}

2 IO → I₂ + O₂

Iodine monoxide reacts with nitric oxide:^[5]

2 IO + 2 NO → I₂ + 2 NO₂

Atmosphere

Atmospheric iodine atoms (e.g. from iodomethane) can react with ozone to produce the iodine monoxide radical:^[6][5]

I₂ + 2 O₃ → 2 IO + 2 O₂

This process can contribute to ozone depletion.^{[citation needed]}