Copper

Copper is a <a href="/facts/Chemical_element/0jducgWD">chemical element</a>; it has <a href="/facts/Chemical_symbol/2Fe1VAL0">symbol</a> Cu (from <a href="/facts/Latin/pM3Kge85">Latin</a> cuprum) and <a href="/facts/Atomic_number/bgAr581S">atomic number</a> 29. It is a soft, malleable, and <a href="/facts/Ductility/SBJsahEk">ductile</a> metal with very high <a href="/facts/Thermal_conductivity/qWnSG3nQ">thermal</a> and <a href="/facts/Electrical_conductivity/akyCKvMy">electrical conductivity</a>. A freshly exposed surface of pure copper has a <a href="/facts/Copper_(color)/oEHKn1js">pinkish-orange color</a>. Copper is used as a conductor of heat and electricity, as a <a href="/facts/Building_material/Kk7GB0KY">building material</a>, and as a constituent of various metal <a href="/facts/Alloy/I7w7WQWR">alloys</a>, such as <a href="/facts/Sterling_silver/fa6mHoon">sterling silver</a> used in <a href="/facts/Jewelry/DYt7cj0R">jewelry</a>, <a href="/facts/Cupronickel/KE4WSdu3">cupronickel</a> used to make marine hardware and <a href="/facts/Coin/PbMTkT2d">coins</a>, and <a href="/facts/Constantan/jFtaIQP2">constantan</a> used in <a href="/facts/Strain_gauge/w12yKexN">strain gauges</a> and <a href="/facts/Thermocouple/FW9cYU5D">thermocouples</a> for temperature measurement.
Copper is one of the few metals that can occur in nature in a directly usable, unalloyed metallic form. This means that copper is a <a href="/facts/Native_metal/gsbV9m3h">native metal</a>. This led to very early human use in several regions, from c. 8000 BC. Thousands of years later, it was the first metal to be <a href="/facts/Smelting/Ghdvhlga">smelted</a> from sulfide ores, c. 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, <a href="/facts/Tin/vxbbBgNz">tin</a>, to create <a href="/facts/Bronze/YCYCVIKt">bronze</a>, c. 3500 BC.
Commonly encountered compounds are copper(II) salts, which often impart blue or green colors to such minerals as <a href="/facts/Azurite/5IutkQYG">azurite</a>, <a href="/facts/Malachite/NG5p4aCv">malachite</a>, and <a href="/facts/Turquoise/vCPfDGPq">turquoise</a>, and have been used widely and historically as pigments.
Copper used in buildings, usually for roofing, oxidizes to form a green <a href="/facts/Patina/IVQsrSMM">patina</a> of compounds called <a href="/facts/Verdigris/c6hG6bbI">verdigris</a>. Copper is sometimes used in <a href="/facts/Decorative_art/w0TpPKvu">decorative art</a>, both in its elemental metal form and in compounds as pigments. Copper compounds are used as <a href="/facts/Bacteriostatic_agent/fdt8GNNb">bacteriostatic agents</a>, <a href="/facts/Fungicide/c1twQBYo">fungicides</a>, and <a href="/facts/Wood_preservative/eLLDnkbE">wood preservatives</a>.
Copper is essential to all living organisms as a trace <a href="/facts/Dietary_mineral/ACv8EG7f">dietary mineral</a> because it is a key constituent of the respiratory enzyme complex <a href="/facts/Cytochrome_c_oxidase/U67QVCv8">cytochrome c oxidase</a>. In <a href="/facts/Molluscs/1elgknsQ">molluscs</a> and <a href="/facts/Crustacean/PBobIVJP">crustaceans</a>, copper is a constituent of the blood pigment <a href="/facts/Hemocyanin/kCxIlQW9">hemocyanin</a>, replaced by the iron-complexed <a href="/facts/Hemoglobin/RsD1MzYA">hemoglobin</a> in fish and other <a href="/facts/Vertebrate/tT54FSTT">vertebrates</a>. In humans, copper is found mainly in the liver, muscle, and bone. The adult body contains between 1.4 and 2.1 mg of copper per kilogram of body weight.

Copper open-in-new

Copper