Hydroxide
Hydroxide is a diatomic anion with chemical formula OH. It consists of an oxygen and hydrogen atom held together by a covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, and a catalyst. The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. A hydroxide attached to a strongly electropositive center may itself ionize, liberating a hydrogen cation (H), making the parent compound an acid.
Hydroxide
"Ortho"-periodic acid can lose all its protons, eventually forming the periodate ion [IO]. It can also be protonated in strongly acidic conditions to give the octahedral ion [I(OH)], completing the isoelectronic series, [E(OH)], E = Sn, Sb, Te, I; "z" = −2, −1, 0, +1. Other acids of iodine(VII) that contain hydroxide groups are known, in particular in salts such as the "meso"periodate ion that occurs in K[IO(OH)]·8HO.