copper (Cu) [L, cuprum] , a malleable, reddish-brown metallic element. Its atomic number is 29; its atomic mass is 63.55. Copper occurs in a pure state in nature and in many ores. It is a component of several important enzymes in the body and is essential to good health. Copper deficiency is rare because only 2 to 5 mg daily, easily obtained from a variety of foods, is sufficient for a proper balance. Copper accumulates in individuals with Wilson’s disease, primary biliary cirrhosis, and, occasionally, chronic extrahepatic biliary tract obstruction. It is an excellent conductor of heat and electricity and a valuable component of numerous alloys, and it may be compounded with arsenic to form insecticides. See also ceruloplasmin, hepatolenticular degeneration.
