copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a soft, ductile metal with a characteristic reddish-brown color and exceptionally high electrical and thermal conductivity.

Copper occurs in nature as native metal and in various ore minerals, including chalcopyrite, bornite, malachite, and azurite. Most copper is obtained from sulfide ores by mining, smelting, and refining, with electrolytic refining producing high-purity copper metal. The metal is highly malleable and can be drawn into wires or formed into sheets. When exposed to air, copper slowly forms a protective patina of copper oxide and carbonate that helps limit further corrosion.

In human history, copper has long been essential. It is alloyed with tin to produce bronze and with zinc to make brass. In modern technology, copper remains indispensable for electrical wiring, plumbing, heat exchangers, architectural applications, and various electronics and industrial uses.

Natural copper comprises two stable isotopes, 63Cu and 65Cu, with approximately 69% and 31% abundances, respectively. The element also has several radioisotopes, but they occur only in trace amounts or under artificial production.

Copper is highly recyclable and can be melted and reformed without loss of quality, contributing to resource conservation and energy savings. Environmental and health considerations focus on copper compounds, which can be toxic in certain forms or concentrations, and on controlling copper discharge into ecosystems.