Copper
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Background
It is believed the Egyptians (as early as 3900 B.C.E.) were the first people to create bronze, a mixture of copper and tin. This marked the beginning of the Bronze Age.
Modern culture and life is heavily dependent on copper and copper products. It is a metal that has the desirable physical properties of being malleable and ductile. Malleable means it can be hammered and molded into shapes; ductile means it can be drawn into wire. As a result, copper pipes are used to bring water to and through our buildings. Because it is such a good conductor of electricity, millions of miles of copper wire crisscross the landscape and run through our buildings. Copper alloys (such as brass) are important components in many household products and machines. It has been said that the amount of copper a society consumes is a direct indicator of the advancement of that society. In other words, those societies that consume larger amounts of copper are considered more technologically developed.
Copper ore may be found in large deposits, relatively close to the surface, and amenable to relatively low cost bulk mining methods. The combination of its physical properties, abundance, and low cost make it a valuable commodity.
Copper is a mineral. As a mineral, natural copper (also called native copper) is relatively rare. Most copper in nature is found in minerals associated with sulfur, or in the oxidized products of these minerals.
Copper also easily combines with a number of other elements and ions to form a wide variety of copper minerals and ores. Copper minerals occurring in deposits large enough to mine include azurite (Cu3(CO3)2(OH)2), malachite (Cu2CO3(OH)2), tennantite ((Cu,Fe)12As4S13), chalcopyrite (CuFeS2), and bornite (Cu5FeS4).
Name
| Previous Element: Nickel Copper Next Element: zinc |
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| Physical Properties | ||
|---|---|---|
| Color | orange-red | |
| Phase at Room Temp. | solid | |
| Density (g/cm3) | 8.95 | |
| Hardness (Mohs) | 2.75 | |
| Melting Point (K) | 1356.6 | |
| Boiling Point (K) | 2843 | |
| Heat of Fusion (kJ/mol) | 13.012 | |
| Heat of Vaporization (kJ/mol) | 305 | |
| Heat of Atomization (kJ/mol) | 338 | |
| Thermal Conductivity (J/m sec K) | 401 | |
| Electrical Conductivity (1/mohm cm) | 595.8 | |
| Source | Cu pyrite, chalcocite | |
| Atomic Properties | ||
| Electron Configuration | [Ar]3d104s1 | |
| Number of Isotopes | 2 | |
| Electron Affinity (kJ/mol) | 118.5 | |
| First Ionization Energy (kJ/mol) | 745.4 | |
| Second Ionization Energy (kJ/mol) | 1957.9 | |
| Third Ionization Energy (kJ/mol) | 3553.5 | |
| Electronegativity | 1.95 | |
| Polarizability (Å3) | 6.7 | |
| Atomic Weight | 63.55 | |
| Atomic Volume (cm3/mol) | 7.1 | |
| Ionic Radius2- (pm) | --- | |
| Ionic Radius1- (pm) | --- | |
| Atomic Radius (pm) | 128 | |
| Ionic Radius1+ (pm) | 91 | |
| Ionic Radius2+ (pm) | 87 | |
| Ionic Radius3+ (pm) | 68 | |
| Common Oxidation Numbers | +2 | |
| Other Oxid. Numbers | +1, +3, +4 | |
| Abundance | ||
| In Earth's Crust (mg/kg) | 6.0×10-1 | |
| In Earth's Ocean (mg/L) | 2.5×10-4 | |
| In Human Body (%) | 0.0001% | |
| Regulatory / Health | ||
| CAS Number | 7440-50-8 | |
| OSHA Permissible Exposure Limit (PEL) | TWA: 1 mg/m3 | |
| OSHA PEL Vacated 1989 | TWA: 1 mg/m3 | |
| NIOSH Recommended Exposure Limit (REL) | TWA: 1 mg/m3 IDLH: 100 mg/m3 | |
| Sources: University of Wisconsin General Chemistry Mineral Information Institute Jefferson Accelerator Laboratory EnvironmentalChemistry.com | ||
Copper was named from the Greek word kyprios, that is, the Island of Cyprus, where copper deposits were mined by the ancients. The chemical symbol for copper is Cu which is derived from the Latin name for copper, cuprium.
Sources
The amount of copper believed to be accessible for mining on the Earth’s land is 1.6 billion tons. In addition, it is estimated that 0.7 billion tons of copper is available in deep-sea nodules. Mineral-rich nodules of magnesium, copper and other metals are known to form as a product of deep-sea volcanic activity. Retrieving these nodules from the sea floor is as yet too expensive to allow this to be a major source of copper.
Of the copper ore mined in the United States, the majority is produced in three western states: Arizona, Utah, and New Mexico.
Other major copper producing nations include Australia, Canada, Chile, China, Mexico, Russia, Peru, and Indonesia.
Recycled copper, predominantly from scrap metal, supplies approximately one-third of the United States’ annual copper needs.
Uses
In pure form, copper is drawn into wires or cables for power transmission, building wiring, motor and transformer wiring, wiring in commercial and consumer electronics and equipment; telecommunication cables; electronic circuitry; plumbing, heating and air conditioning tubing; roofing, flashing and other construction applications; electroplated coatings and undercoats for nickel, chrome, zinc, etc.; and miscellaneous applications. As an alloy with tin, zinc, lead, etc. (brass and bronze), it is used in extruded, rolled or cast forms in plumbing fixtures, commercial tubing, electrical contacts, automotive and machine parts, decorative hardware, coinage, ammunition, and miscellaneous consumer and commercial uses. Copper is an essential micronutrient used in animal feeds and fertilizers.
Substitutes and Alternative Sources
A number of plastic products are used now instead of copper pipes. The telecommunications industry is using fiber optic cables in place of copper wires, and the invention of cellular and satellite telephone technology allows many areas of the world to have communications without the need to install “copper telephone wires.” Aluminum can be used instead of copper for wires, refrigeration tubing, and electrical equipment.
Further Reading
- Common Minerals and Their Uses, Mineral Information Institute.
- More than 170 Mineral Photographs, Mineral Information Institute.
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