|Name, Symbol, Number||copper, Cu, 29|
|Chemical series||transition metals|
|Group, Period, Block||11, 4 , d|
|Density, Hardness||8920 kg/m3, 3.0|
|Atomic weight||63.536 amu|
|Atomic radius (calc.)||135 (145) pm|
|Covalent radius||138 pm|
|van der Waals radius||140 pm|
|e- 's per energy level||2, 8, 18, 1|
|Oxidation states (Oxide)||2,1 (mildly basic)|
|Crystal structure||cubic, face-centered|
|State of matter||solid (__)|
|Melting point||1357.6 K (1984.3 ðF)|
|Boiling point||2840 K (4653 ðF)|
|Molar volume||7.11 ×1010-6 m3/mol|
|Heat of vaporization||300.3 kJ/mol|
|Heat of fusion||13.05 kJ/mol|
|Vapor pressure||0.0505 Pa at 1358 K|
|Speed of sound||3570 m/s at 293.15 K|
|Electronegativity||1.9 (Pauling scale)|
|Specific heat capacity||380 J/(kg*K)|
|Electrical conductivity||59.6 106/m ohm|
|Thermal conductivity||401 W/(m*K)|
|1st ionization potential||745.5 kJ/mol|
|2nd ionization potential||1957.9 kJ/mol|
|3rd ionization potential||3555 kJ/mol|
|4th ionization potential||5536 kJ/mol|
|Most stable isotopes|
|SI units & STP are used except where noted.|
|Table of contents|
4 Biological role
10 External links
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 may well be the oldest metal in use, as copper artifacts dating to 8700 BC have been found. Besides being part of various ores, copper can be found in the metallic form ( i.e. native copper) in some locations.
In Greek times, the metal was known by the name Chalkos. In Roman times, it became known as aes Cyprium, because so much of it was mined in Cyprus. From this, the phrase was simplified to cuprum and then Anglicized into the English copper.
Copper is malleable and ductile, and is used extensively, in products such as:
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 oxides such as malachite or azurite. The earliest signs of gold use, by contrast, appear around 4000 BC.
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. 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 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 BCE, 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.
Copper is essential in all higher plants and animals. 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.
The RDA for copper in normal healthy adults is 0.9 mg/day.
OccurrenceCopper is usually found in a mineral form. Minerals such as azurite, malachite and bornite are sources of copper, as are sulfides such as chalcopyrite (CuFeS2), coveline (CuS), chalcosine (Cu2S) or oxides like cuprite (Cu2O).
Common oxidation states of copper include the copper (I) state, Cu+1, and copper (II) state, Cu+2.
Copper carbonate is green from which arises the unique appearance of copper-clad roofs or domes on some buildings.
Other compounds : copper (II) sulfide
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.
All copper compounds, unless otherwise known, should be treated as if they were toxic.The metal, when powdered, is a fire hazard. 30g of copper sulfate is potentially lethal in humans. Copper in drinking water at concentrations higher than 1 mg/liter can stain clothes and items washed in water. 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/liter.