Copper (Cu) is a metallic element known to humans since the Bronze Age. This reddish-brown, malleable, ductile metal is a very good conductor of heat and electricity. It has low chemical reactivity. In moist air it forms a patina, which is a protective, greenish surface film. The primary commercial uses of copper are in electrical apparatus and wire, roofing, utensils, coins, metalwork, plumbing, and condensing coils. Copper alloys include brass and bronze. Copper compounds are used as insecticides, fungicides, and paint pigments. They are also used in electroplating. Copper is an essential nutrient for normal human metabolism and hemoglobin synthesis in blood.
