The hypochlorite ion, ClO-, is the negative ion of hypochlorous acid, HOCl. It is produced when molecular chlorine, Cl2, is dissolved in water or in a solution of sodium hydroxide, NaOH. It is also produced industrially from the hydrolysis of a cold solution of sodium chloride, NaCl.
The hypochlorite ion forms different salts with metals. Typical examples are sodium hypochlorite, NaOCl, and calcium hypochlorite, Ca(OCl)2. Hypochlorite salts are used as bleaches, disinfectants and for water treatment due to their oxidizing and chlorinating effects. The hypochlorite ion is unstable and decomposes into a mixture of chloride ions, Cl-, chlorate ions, O3Cl- and molecular oxygen, O2.