The anion (negatively charged ion) Cl is the anion (chloride ion). It is generated when the element chlorine (a halogen) gets an electron or when a molecule such as hydrogen chloride is dissolved in water or other polar solvents. Chloride compounds like sodium chloride are frequently extremely soluble in water.  It is an electrolyte found in all bodily fluids that is responsible for maintaining acid/base balance, sending nerve impulses, and controlling liquid movement in and out of cells. Less commonly, the term chloride may appear as part of the “common” name of a chemical compound containing one or more covalently bound chlorine atoms. For instance, methyl chloride, often known as chloromethane (see IUPAC volumes), is an organic molecule having a covalent CCl link in which the chlorine is not an anion.