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Copper

2007 Schools Wikipedia Selection. Related subjects: Chemical elements


                29                 nickel ← copper → zinc
                 -
                ↑
                Cu
                ↓
                Ag

                                  Periodic Table - Extended Periodic Table

                                                                   General
                                       Name, Symbol, Number copper, Cu, 29
                                         Chemical series transition metals
                                             Group, Period, Block 11, 4, d
                                           Appearance metallic pinkish red
                                              Atomic mass 63.546 (3) g/mol
                                    Electron configuration [Ar] 3d^10 4s^1
                                           Electrons per shell 2, 8, 18, 1
                                                       Physical properties
                                                               Phase solid
                                       Density (near r.t.) 8.96 g·cm^−3
                                    Liquid density at m.p. 8.02 g·cm^−3
                                                  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^−1
                                   Heat of vaporization 300.4 kJ·mol^−1
                         Heat capacity (25 °C) 24.440 J·mol^−1·K^−1

   CAPTION: 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 face centered cubic
                                                     Oxidation states 2, 1
                                                      (mildly basic oxide)
                                    Electronegativity 1.90 (Pauling scale)
                                                       Ionization energies
                                           ( more) 1st: 745.5 kJ·mol^−1
                                                  2nd: 1957.9 kJ·mol^−1
                                                    3rd: 3555 kJ·mol^−1
                                                      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^−1·K^−1
                       Thermal expansion (25 °C) 16.5 µm·m^−1·K^−1
                              Speed of sound (thin rod) ( r.t.) (annealed)
                                                          3810   m·s^−1
                                                   Young's modulus 130 GPa
                                                      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
                                                         Selected isotopes

                  CAPTION: 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

                                                                References

   Copper exists as a metallically bonded substance, allowing it to have a
   wide variety of metallic properties.
   Enlarge
   Copper exists as a metallically bonded substance, allowing it to have a
   wide variety of metallic properties.

   Copper ( IPA: /ˈkɒpə/) is a chemical element in the periodic table that
   has the symbol Cu ( Latin: cuprum) and atomic number 29. It is a
   ductile metal with excellent electrical conductivity, and finds
   extensive use as an electrical conductor, thermal conductor, as a
   building material, and as a component of various alloys.

   Copper is an essential nutrient to all higher plants and animals. In
   animals, it is found primarily in the bloodstream, as a cofactor in
   various enzymes, and in copper-based pigments. In sufficent amounts,
   copper can be poisonous or even fatal to organisms.

   Copper has played a significant part in the history of mankind, which
   has used the easily accessible uncompounded metal for nearly 10,000
   years. Civilizations in places like Iraq, China, Egypt, Greece and the
   Sumerian cities all have early evidence of using copper, and Britain
   and the United States also have extensive histories of copper use and
   mining. During the Roman Empire, copper was principally mined on
   Cyprus, hence the origin of the name of the metal as Cyprium, "metal of
   Cyprus", later shortened to Cuprum. A number of countries, such as
   Chile and the United States, still have sizeable reserves of the metal
   which are extracted through large open mines. Nevertheless, the price
   of copper rose rapidly—quintupling from a 60-year low in 1999—largely
   due to increased demand. As of mid-2006, the price has stabilized.

Notable characteristics

   Copper just above its melting point keeps its pink luster color when
   enough light overshines the orange incandescence color.
   Enlarge
   Copper just above its melting point keeps its pink luster color when
   enough light overshines the orange incandescence colour.

   Copper is a reddish-colored metal, with a high electrical and thermal
   conductivity (silver is the only pure metal to have a higher electrical
   conductivity at room temperature). In oxidation copper is mildly basic.
   Copper has its characteristic colour because it reflects red and orange
   light and absorbs other frequencies in the visible spectrum, due to its
   band structure. This can be contrasted with the optical properties of
   silver, gold and aluminium.

   Copper occupies the same family of the periodic table as silver and
   gold, because it shares many characteristics with these metals. All
   have very high thermal and electrical conductivity, and all are
   malleable metals.

   In its liquid state, a clear copper surface without ambient light
   appears somewhat greenish, another characteristic shared with gold.
   Silver does not have this property, so it is not a complementary color
   for the orange incandescence colour. When liquid copper is in bright
   ambient light, it retains some of its pinkish luster. Due to its high
   surface tension, the liquid metal does not wetten surfaces but instead
   forms spherical droplets when poured on a surface.

   Copper is insoluble in water (H[2]O) as well as in isopropanol, or
   isopropyl alcohol.

   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.

   Numerous alloys of copper exist, many with important historical and
   contemporary uses. Speculum metal and bronze are alloys of copper and
   tin. Brass is an alloy of copper and zinc. Monel metal, also called
   cupronickel, is an alloy of copper and nickel. While the metal "bronze"
   usually refers to copper-tin alloys, it also is a generic term for any
   alloy of copper, such as aluminium bronze, silicon bronze, and
   manganese bronze.

   The purity of copper is expressed as 4N for 99.99% pure or 7N for
   99.99999% pure. The numeral gives the number of nines after the decimal
   point when expressed as a decimal (eg 4N means 0.9999, or 99.99%).

Applications

   Copper is malleable and ductile, a good conductor of heat and, when
   very pure, a good conductor of electricity.

   It is used extensively, in products such as:
     * Electronics:
          + Copper wire.
          + Electromagnets.
          + Electrical machines, especially electromagnetic motors and
            generators.
          + Electrical relays, electrical busbars and electrical switches.
          + Vacuum tubes, cathode ray tubes, and the magnetrons in
            microwave ovens.
          + Wave guides for microwave radiation.
          + Integrated circuits, increasingly replacing aluminium because
            of its superior electrical conductivity.
          + As a material in the manufacture of computer heat sinks, as a
            result of its superior heat dissipation capacity to aluminium.

   Copper roof on the Minneapolis City Hall
   Enlarge
   Copper roof on the Minneapolis City Hall
     * Structural Engineering:
          + Statuary: The Statue of Liberty, for example, contains 179,200
            pounds (81.3 tonnes) of copper.
          + Alloyed with nickel, e.g. cupronickel and Monel, used as
            corrosive resistant materials in shipbuilding.
          + Watt's steam engine.

     * Household Products:
          + Copper plumbing fittings and compression tubes.
          + Doorknobs and other fixtures in houses.
          + Roofing, guttering, and rainspouts on buildings.
          + 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.
          + Copper was sometimes used by the Inuit to make the cutting
            blade for ulus.
          + Copper water heating cylinders

     * Coinage:
          + As a component of coins, often as cupronickel alloy.
          + Euro coins contain different copper alloys
          + U.S. Pennies are 2.5% copper by weight (Balance zinc 97.5%).
          + U.S. Nickels are 75.0% copper by weight (Balance nickel
            25.0%).
          + U.S. Dimes and Quarters are 91.67% copper by weight (Balance
            nickel 8.33%).

     * Biomedical applications:
          + As a biostatic surface in hospitals, and to line parts of
            ships to protect against barnacles and mussels, originally
            used pure, but superseded 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 suppressed by copper
            tubing in air-conditioning systems.
          + Copper(II) sulfate is used as a fungicide and as algae control
            in domestic lakes and ponds. It is used in gardening powders
            and sprays to kill mildew.
          + Copper-62-PTSM, a complex contaning radioactive copper-62, is
            used as a Positron emission tomography radiotracer for heart
            blood flow measurements.

     * Chemical applications:
          + Compounds, such as Fehling's solution, have applications in
            chemistry.
          + As a component in ceramic glazes, and to colour glass.

     * Catalysis:
          + Used in the Water gas shift reaction which converts carbon
            monoxide into carbon dioxide.
          + Steam reforming which extracts hydrogen from hydrocarbons.

     * Others:
          + Musical instruments, especially brass instruments and cymbals.

History

   The Egyptians found that adding a small amount of tin made the metal
   easier to cast, so bronze alloys were found in Egypt almost as soon as
   copper was found. Use of copper in ancient China dates to at least 2000
   BC. By 1200 BC 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 BC, 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. Brass, an alloy of zinc and copper, was
   known to the Greeks but first used extensively by the Romans.

   There are copper and bronze artifacts from Sumerian cities that date to
   3000 BC, 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.

   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
   Cyprium 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 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.

   Copper, as native copper, is one of the few metals to naturally occur
   as an uncompounded mineral. 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 BC. By 5000 BC, there are signs of copper
   smelting, the refining of copper from simple copper compounds such as
   malachite or azurite. Among archaeological sites in Anatolia, Çatal
   Höyük (~6000 BC) features native copper artifacts and smelted lead
   beads, but no smelted copper. But Can Hasan (~5000 BC) had access to
   smelted copper; this site has yielded the oldest known cast copper
   artifact, a copper mace head.
   Ancient Copper ingot from Zakros, Crete is shaped in the form of an
   animal skin typical for that era.
   Enlarge
   Ancient Copper ingot from Zakros, Crete is shaped in the form of an
   animal skin typical for that era.

   Copper smelting appears to have been developed independently in several
   parts of the world. In addition to its development in Anatolia by 5000
   BC, it was developed in China before 2800 BC, in Central America around
   600 AD, and in West Africa around 900 AD.

   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.

Copper mining in Britain and the United States

   Copper has been mined for many centuries. By 2000 BC, Europe was using
   copper-tin alloys or ‘bronze’. The Bronze Age is taken as 2500 BC to
   600 BC.
   West Mine at Alderley Edge
   Enlarge
   West Mine at Alderley Edge

British Isles

   During the Bronze age, copper was mined in the British Isles mainly in
   the following locations:
     * South West County Cork
     * West Wales (e.g. Cwmwystwyth)
     * North Wales (e.g. Great Orme)
     * Anglesey (Parys Mountain)
     * Cheshire ( Alderley Edge)
     * The Staffordshire Moorlands (e.g. Ecton Mine)
     * Isle of Man, which is between England and Northern Ireland

   At Great Orme in North Wales, such working extended for a depth of 70
   metres. At Alderley Edge in Cheshire, carbon dates have established
   mining at around 2280 - 1890 BC (at 95% probability).

United States

   Miners at the Tamarack Mine in Copper Country, Michigan, USA in 1905.
   Enlarge
   Miners at the Tamarack Mine in Copper Country, Michigan, USA in 1905.

   Copper mining in United States began with marginal workings by Native
   Americans and some development by early Spaniards. Europeans were
   mining copper in Connecticut as early as 1709. Westward movement also
   brought an expansion of copper exploitation with developments of
   significant deposits in Michigan and Arizona during the 1850's and then
   in Montana during the 1860's.

   Copper was mined extensively in Michigan's Keweenaw Peninsula with the
   heart of extraction at the productive Quincy Mine. Arizona had many
   notable deposits including the Copper Queen in Bisbee and the United
   Verde in Jerome. The Anaconda in Butte, Montana became the nation's
   chief copper supplier by 1886.

   Copper has also been made in Utah, Nevada and Tennessee, and among
   other locations.

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 and the enzyme superoxide
   dismutase (containing copper and zinc). In addition to its enzymatic
   roles, copper is used for biological electron transport. The blue
   copper proteins that participate in electron transport include azurin
   and plastocyanin. The name "blue copper" comes from their intense blue
   colour arising from a ligand-to-metal charge transfer (LMCT) absorption
   band around 600 nm.

   Most molluscs and some arthropods such as the horseshoe crab use the
   copper-containing pigment hemocyanin rather than iron-containing
   hemoglobin for oxygen transport, so their blood is blue when oxygenated
   rather than red.

   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. Thirty grams 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. In toxicity, copper can inhibit
   the enzyme dihydrophil hydratase, an enzyme involved in haemopoiesis.

   A significant portion of the toxicity of copper comes from its ability
   to accept and donate single electrons as it changes oxidation state.
   This catalyzes the production of very reactive radical ions such as
   hydroxyl radical in a manner similar to fenton chemistry. This
   catalytic activity of copper is used by the enzymes that it is
   associated with and is thus only toxic when unsequestered and
   unmediated. This increase in unmediated reactive radicals is generally
   termed oxidative stress and is an active area of research in a variety
   of diseases where copper may play an important but more subtle role
   than in acute toxicity.

   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.

   Too much copper in water has also been found to damage marine life. The
   observed effect of these higher concentrations on fish and other
   creatures is damage to gills, liver, kidneys, and the nervous system.

Occurrence

   Chuquicamata (Chile). The largest open pit copper mine in the world.
   Enlarge
   Chuquicamata (Chile). The largest open pit copper mine in the world.

   The main copper ore producing countries are Chile, United States,
   Indonesia, Australia, Peru, Russia, Canada, China, Poland, Kazakhstan
   and Mexico.

   Copper can be found as native copper in mineral form. Minerals such as
   the sulfides: chalcopyrite (CuFeS[2]), bornite (Cu[5]FeS[4]), covellite
   (CuS), chalcocite (Cu[2]S) are sources of copper, as are the
   carbonates: azurite (Cu[3](CO[3])[2](OH)[2]) and malachite
   (Cu[2]CO[3](OH)[2]) and the oxide: cuprite (Cu[2]O). Native copper also
   forms in uneconomic placer deposits.

   Most copper ore is mined or extracted as copper sulfides from large
   open pit mines in porphyry copper 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 68 ppm by mass, and 22 ppm by atoms.
   Native Copper Placer Nuggets
   Enlarge
   Native Copper Placer Nuggets
   Native copper
   Enlarge
   Native copper

   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.

   The copper price has quintupled since 1999, rising from $0.60 per pound
   in June 1999 to $3.75 per pound in May 2006 .

Compounds

   Common oxidation states of copper include the less stable copper(I)
   state, Cu^+; and the more stable copper(II) state, Cu^2+, which forms
   blue or blue-green salts and solutions. Under unusual conditions, a 3+
   state and even an extremely rare 4+ 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 penta hydrate which is perhaps the most
   familiar copper compound in the laboratory. It is used as a fungicide,
   known as Bordeaux mixture.

   There are two stable copper oxides, copper(II) oxide (CuO) and
   copper(I) oxide (Cu[2]O). Copper oxides are used to make yttrium barium
   copper oxide (YBa[2]Cu[3]O[7-δ]) or YBCO which forms the basis of many
   unconventional superconductors.
     * Copper (I) compounds : copper(I) chloride, copper(I) bromide,
       copper(I) iodide, copper(I) oxide.

     * Copper (II) compounds : copper(II) carbonate, copper(II) chloride,
       copper(II) hydroxide, copper(II) nitrate, copper(II) oxide,
       copper(II) sulfate, copper(II) sulfide.

     * Copper (III) compounds , rare: potassium hexafluorocuprate
       (K[3]CuF[6])

     * Copper (IV) compounds , extremely rare: caesium hexafluorocuprate
       (Cs[2]CuF[6])

   Copper (I) and Copper (II) can also be referred to by their common
   names cuprous and cupric.

Tests for copper(II) 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:

          Cu^2+(aq) + 2OH^−(aq) → Cu(OH)[2](s)

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

   Ionic equation:

          Cu^2+(aq) + 4NH[3](aq) → [Cu(NH[3])[4]]^2+(aq)

   Retrieved from " http://en.wikipedia.org/wiki/Copper"
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