Copper

For other uses, see Copper (disambiguation).

29 nickel ← copper → zinc - ↑ Cu ↓ Ag periodic table
General
Name, Symbol, Number	copper, Cu, 29
Chemical series	transition metals
Group, Period, Block	11, 4, d
Appearance	metallic brown
Atomic mass	63.546(3) g/mol
Electron configuration	[Ar] 3d10 4s1
Electrons per shell	2, 8, 18, 1
Physical properties
Phase	solid
Density (near r.t.)	8.96 g/cm³
Liquid density at m.p.	8.02 g/cm³
Melting point	1357.77 K (1084.62 °C, 1984.32 °F)
Boiling point	2835 K (2562 °C, 4643 °F)
Heat of fusion	13.26 kJ/mol
Heat of vaporization	300.4 kJ/mol
Heat capacity	(25 °C) 24.440 J/(mol·K)
Vapor pressure P/Pa 1 10 100 1 k 10 k 100 k at T/K 1509 1661 1850 2089 2404 2836
Atomic properties
Crystal structure	cubic face centered
Oxidation states	2, 1 (mildly basic oxide)
Electronegativity	1.90 (Pauling scale)
Ionization energies (more)	1st: 745.5 kJ/mol
	2nd: 1957.9 kJ/mol
	3rd: 3555 kJ/mol
Atomic radius	135 pm
Atomic radius (calc.)	145 pm
Covalent radius	138 pm
Van der Waals radius	140 pm
Miscellaneous
Magnetic ordering	diamagnetic
Electrical resistivity	(20 °C) 16.78 nΩ·m
Thermal conductivity	(300 K) 401 W/(m·K)
Thermal expansion	(25 °C) 16.5 µm/(m·K)
Speed of sound (thin rod)	(r.t.) (annealed) 3810 m/s
Speed of sound (thin rod)	(r.t.) 130 m/s
Shear modulus	48 GPa
Bulk modulus	140 GPa
Poisson ratio	0.34
Mohs hardness	3.0
Vickers hardness	369 MPa
Brinell hardness	874 MPa
CAS registry number	7440-50-8
Notable isotopes
Main article: Isotopes of copper iso NA half-life DM DE (MeV) DP 63Cu 69.17% Cu is stable with 34 neutrons 65Cu 30.83% Cu is stable with 36 neutrons

Copper is a chemical element in the periodic table that has the symbol Cu and atomic number 29.

History

In Greek times, the metal was known by the name chalkos (χαλκός). Copper was a very important resource for the Romans and Greeks. In Roman times, it became known as aes Cyprium (aes being the generic Latin term for copper alloys such as bronze and other metals, and because so much of it was mined in Cyprus). From this, the phrase was simplified to cuprum and then eventually Anglicized into the English copper.

Copper was known to some of the oldest civilizations on record, and has a history of use that is at least 10,000 years old. A copper pendant was found in what is now northern Iraq that dates to 8700 B.C.E. By 5000 B.C.E. there are signs of copper smelting, the refining of copper from simple copper oxides such as malachite or azurite. The earliest signs of gold use, by contrast, appear around 4000 B.C.E.

There are copper and bronze artifacts from Sumerian cities that date to 3000 B.C.E., and Egyptian artifacts in copper and copper alloyed with tin nearly as old. In one pyramid, a copper plumbing system was found that is 5000 years old.

Ancient Copper ingot from Zakros, Crete. The ingot is shaped in the form of an animal skin, a typical shape of copper ingots from these times.

The Egyptians found that adding a small amount of tin made the metal easier to cast, so bronze alloys are found in Egypt almost as soon as copper is found. Use of copper in ancient China dates to at least 2000 B.C.E. By 1200 B.C.E. excellent bronzes were being made in China. Note that these dates are affected by wars and conquest, as copper is easily melted down and reused. In Europe, Oetzi the Iceman, a well preserved male dated to 3200 B.C.E., was found with a copper tipped axe whose metal was 99.7% pure. High levels of arsenic in his hair suggests he was involved in copper smelting.

The use of bronze was so pervasive in a certain era of civilization that it has been named the Bronze Age. The transitional period in certain regions between the preceding Neolithic period and the Bronze Age is termed the Chalcolithic, with some high purity copper tools being used alongside stone tools.

Alchemical symbol for copper

Brass, an alloy of zinc and copper, was known to the Greeks but first used extensively by the Romans.

Copper was associated with the goddess Aphrodite/Venus in mythology and alchemy, owing to its lustrous beauty, its ancient use in producing mirrors, and its association with Cyprus, which was sacred to the goddess.

In alchemy the symbol for copper was also the symbol for the planet Venus.

Biological role

Copper is essential in all higher plants and animals. Copper is carried mostly in the bloodstream on a plasma protein called ceruloplasmin. When copper is first absorbed in the gut it is transported to the liver bound to albumin. Copper is found in a variety of enzymes, including the copper centers of cytochrome c oxidase, the Cu-Zn containing enzyme superoxide dismutase, and is the central metal in the oxygen carrying pigment hemocyanin. The blood of the horseshoe crab, Limulus polyphemus uses copper rather than iron for oxygen transport.

It is believed that zinc and copper compete for absorption in the digestive tract so that a diet that is excessive in one of these minerals may result in a deficiency in the other. The RDA for copper in normal healthy adults is 0.9 mg/day.

Toxicity

All copper compounds, unless otherwise known, should be treated as if they were toxic. 30g of copper sulfate is potentially lethal in humans. The suggested safe level of copper in drinking water for humans varies depending on the source, but tends to be pegged at 1.5 to 2 mg/l. The DRI Tolerable Upper Intake Level for adults of dietary copper from all sources is 10 mg/day.

An inherited condition called Wilson's disease causes the body to retain copper, since it is not excreted by the liver into the bile. This disease, if untreated, can lead to brain and liver damage. In addition, studies have found that people with mental illnesses such as schizophrenia had heightened levels of copper in their systems. However it is unknown at this stage whether the copper contributes to the mental illness, whether the body attempts to store more copper in response to the illness, or whether the high levels of copper are the result of the mental illness.

Miscellaneous hazards

The metal, when powdered, is a fire hazard. At concentrations higher than 1 mg/L, copper can stain clothes and items washed in water.

Physical characteristics

Copper is a reddish-coloured metal, with a high electrical and thermal conductivity (among pure metals at room temperature, only silver has a higher electrical conductivity). Copper has its characteristic color because it reflects red and orange light and absorbs other frequencies in the visible spectrum, due to its band structure.

There are two stable isotopes, ⁶³Cu and ⁶⁵Cu, along with a couple dozen radioisotopes. The vast majority of radioisotopes have half lives on the order of minutes or less, the longest lived, ⁶⁴Cu, has a half life of 12.7 hours, with two decay modes, leading to two separate products.

There are numerous alloys of copper - speculum metal is a copper/tin alloy, brass is a copper/zinc alloy, and bronze is a copper/tin alloy. Monel metal is a copper/nickel alloy, also called cupronickel.

Compounds

Native copper

Common oxidation states of copper include the less stable copper(I) state, Cu⁺¹; and the more stable copper(II) state, Cu⁺², which forms lovely blue or blue-green salts. Under unusual conditions, a +3 state can be obtained.

Copper(II) carbonate is green from which arises the unique appearance of copper-clad roofs or domes on some buildings. Copper(II) sulfate forms a blue crystalline pentahydrate which is perhaps the most familiar copper compound in the laboratory. It is used as a fungicide, known as Bordeau mixture.

There are two stable copper oxides, copper(II) oxide (CuO) and copper(I) oxide (Cu₂O). Copper oxides are used to make yttrium barium copper oxide (YBa₂Cu₃O_7-δ) or YBCO which forms the basis of many unconventional superconductors.

Other compounds : Copper(I) chloride, copper(II) chloride, copper(II) sulfide.

Occurrence

The El Chino open-pit copper mine in New Mexico.

See Copper extraction for the main article.

Copper can be found as native copper in mineral form. Minerals such as the carbonates azurite (Cu₃(CO₃)₂(OH)₂) and malachite (Cu₂CO₃(OH)₂) are sources of copper, as are sulfides such as chalcopyrite (CuFeS₂), bornite (Cu₅FeS₄), covellite (CuS), chalcocite (Cu₂S) and oxides like cuprite (Cu₂O).

Most copper ore is mined or extracted from large open pit mines in copper porphyry deposits that contain 0.4 to 1.0 percent copper. Examples include: Chuquicamata in Chile and El Chino mine in New Mexico. The average abundance of copper found within crustal rocks is approximately 68000 parts per billion by mass, and 22000 parts per billion by atoms.

The Intergovernmental Council of Copper Exporting Countries (CIPEC), defunct since 1992, once tried to play a similar role for copper as OPEC does for oil, but never achieved the same influence, not least because the second-largest producer, the United States, was never a member. Formed in 1967, its principal members were Chile, Peru, Zaire, and Zambia.

Tests for copper²⁺ ion

Add aqueous sodium hydroxide. A blue precipitate of copper(II) hydroxide should form, by the displacement of the copper ions by sodium ions.

Ionic equation:

Cu²⁺_(aq) + 2OH^-_(aq) -> Cu(OH)_{2 (s)}

Add aqeuous ammonia. A precipitate should form, which then dissolves upon adding excess ammonia, to form an ammonia complex, tetraaminecopper(II).

Ionic equation:

Cu²⁺_(aq) + 4NH_{3 (aq)} -> Cu(NH₃)₄²⁺_(aq)

Applications

Copper is malleable and ductile, and is used extensively, in products such as:

• Copper wire.
• Copper plumbing.
• Doorknobs and other fixtures in houses.
• Statuary: The Statue of Liberty, for example, contains 179,200 pounds (81.3 tonnes) of copper.
• Electromagnets.
• Motors, especially electromagnetic motors.
• Watt's steam engine.
• Electrical relays, electrical busbars and electrical switches.
• Vacuum tubes, cathode ray tubes, and the magnetrons in microwave ovens.
• Wave guides for microwave radiation.
• There is increasing use of copper in integrated circuits, replacing aluminium because of its superior conductivity.
• Alloyed with nickel, e.g. cupronickel and Monel, used as corrosive resistant materials in shipbuilding.
• As a component of coins, often as cupronickel alloy.
• In cookware, such as frying pans.
• Most flatware (knives, forks, spoons) contains some copper (nickel silver).
• Sterling silver, if it is to be used in dinnerware, must contain a few percent copper.
• As a component in ceramic glazes, and to color glass.
• Musical instruments, especially brass instruments.
• As a biostatic surface in hospitals, and to line parts of ships to protect against barnacles and mussels, originally used pure, but superceded by Muntz Metal. Bacteria will not grow on a copper surface because it is biostatic. Copper doorknobs are used by hospitals to reduce the transfer of disease, and Legionnaire's Disease is supressed by copper tubing in air-conditioning systems.
• Compounds, such as Fehling's solution, have applications in chemistry.
• Copper(II) sulfate is used as a poison and a water purifier. It is used in gardening powders and sprays to kill mildew.

References

ISBN links support NWE through referral fees

• Los Alamos National Laboratory - Copper
• Copper: Technology & Competitiveness (Summary) Chapter 6: Copper Production Technology; Author: Office of Technology Assessment 2005

External links

• WebElements.com – Copper
• Copper Toxicity Syndrome
• Copper- Benefits, Deficiency Symptoms And Food Sources
• The Copper Page
• Photos of the Parys Mountain Copper Mine near Amlwch, Anglesey, Wales
• Current copper price as at June 2005, about USD$3,500 / tonne.
• World mine production of copper by country

af:Koper bg:Мед ca:Coure cs:Měď cy:Copr da:Kobber de:Kupfer et:Vask es:Cobre eo:Kupro fa:مس (فلز) fr:Cuivre ko:구리 hr:Bakar io:Kupro is:Kopar it:Rame he:נחושת kw:Kober ku:Sifir la:Cuprum lv:Varš lt:Varis hu:Réz mk:Бакар mi:Konukura nl:Koper (element) nds:Kopper ja:銅 no:Kobber nn:Kopar oc:Coire pl:Miedź pt:Cobre ro:Cupru ru:Медь simple:Copper sl:Baker sr:Бакар (хемијски елемент) fi:Kupari sv:Koppar th:ทองแดง vi:Đồng (nguyên tố) tr:Bakır uk:Мідь zh:铜

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

• Copper  ^history

The history of this article since it was imported to New World Encyclopedia:

• History of "Copper"

Note: Some restrictions may apply to use of individual images which are separately licensed.