Symbol Cu, bright red tough and ductile metal. Upon exposure to moist air, copper generates an adherent layer of Cu(I) oxide. In the presence of CO2, SO2, chlorides, etc. a greenish patina forms protecting the underlying metal from further corrosion. Pure copper is widely used as conducting material in electrical industry. Due to its chemical stability and high conductivity it is employed for vessels, heating pipes, cooling pipes, etc. Copper coatings are available by electroplating.