Hypohalite


Hypohalites are chemical compounds containing the hypohalite ion, with the general formula XO⁻, where X is a halogen element from Group 17 of the periodic table. Hypohalites are the conjugate bases of hypohalous acids and represent the lowest oxidation state of halogens in their oxoanions.Hypohalites are also encountered in organic chemistry, often as acyl hypohalites. Sodium hypohalite is used in the haloform reaction as a test for methyl ketones.

Structure

The hypohalite ion consists of a halogen atom covalently bonded to an oxygen atom, carrying an overall negative charge. The halogen is in the +1 oxidation state, and the oxygen is in the usual −2 state. The general formula is:
XO-
  • X is the halogen atom, and
  • O is the oxygen atom
The Cl-O bond length in crystalline sodium hypochlorite pentahydrate, NaOCl·5H2O, is 1.686 Å, while in sodium hypobromite pentahydrate, NaOBr·5H2O, the Br–O bond length is 8% longer at 1.820 Å.