The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl-. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. An example is table salt, which is sodium chloride with the chemical formula NaCl. In water, it dissolves into Na+ and Cl- ions. The word chloride can also refer to a chemical compound

Copper(II) chloride is the chemical compound with the formula CuCl2. This a yellow-brown solid which slowly absorbs moisture to form a blue-green dehydrate.