Project Watershed Central New York

The chloride ion is formed when the element chlorine picks up one electron to form the negatively charged ion Cl?. The salts of hydrochloric acid HCl are also called chlorides. An example is table salt, which is sodium chloride with the formula NaCl. In water, it dissociates into Na+ and Cl? ions.

Chloride ions have important physiological roles. For instance, in the central nervous system the inhibitory action of glycine and some of the action of GABA relies on the entry of Cl? into specific neurons.

Nitrogen trichloride is a yellow oily liquid somewhat resembling nitroglycerine. Trademarked as Agene, it was formerly used to artificially bleach and age flour but now is found in small amounts as a result of chlorinating water. Sometimes known as 'the Devil's sweat', it is little-known outside of the bleaching industry but a rather unfriendly chemical. When purified, it is highly unstable and explodes on contact with organic compounds or catalytic surfaces, by impacts and shock waves, or by self-heating during its decomposition. Bubbling chlorine gas through a solution of ammonium nitrate yields yellow droplets of nitrogen trichloride.