Iodine forms chemical compounds in several oxidation states: -1, +1, +3, +5, and +7. This is typical of the halogens except for fluorine. -1 compounds as iodides are the most common. Most organic iodine compounds are in the -1 oxidation state. Most iodides are colorless or reddish-yellow and are weak reducing agents. +1 and +3 compounds are quite rare. They are both oxidizing agents. +1 compounds are found as iodine monochloride and hypoiodites. +3 compounds are found as iodine trichloride or iodine trifluoride. +5 compounds are found as iodates and iodic acid. Iodine pentafluoride and iodine pentoxide are iodine compounds in the +5 state. +5 and +7 compounds are all strong oxidizing agents. +7 compounds are normally found as periodates and periodic acid. Iodine heptafluoride is also in the +7 oxidation state.