Iodine pentoxide, also known as iodine(V) oxide and diiodine pentoxide is a chemical compound. Its chemical formula is I2O5. It has iodine and oxide ions. The iodine is in its +5 oxidation state.
Iodine pentoxide is a white solid. It breaks down to iodine and oxygen when heated. It reacts with carbon monoxide to make carbon dioxide and iodine. It is a strong oxidizing agent. It reacts with water to make iodic acid.
Iodine pentoxide is made by heating iodic acid to 200 °C (392 °F) in dry air.
It is used to see how much carbon monoxide is in a sample of gas.