Carbon

History and etymology

The English name carbon comes from the Latin carbo for coal and charcoal,^[7] and hence comes French charbon, meaning charcoal. In German, Dutch and Danish, the names for carbon are Kohlenstoff, koolstof and kulstof respectively, all literally meaning coal-substance.

    Carbon was discovered in prehistory and was known in the forms of charcoal was made around Roman times by the same chemistry as it is today, by heating wood in a pyramid covered with clay to exclude air.^[8][9]

In 1722, René A. F. de Réaumur demonstrated that iron was transformed into steel through the absorption of some substance, now known to be carbon.^[10] In 1772, gram. element in his 1789 textbook.^[13]

A new amorphous.^[16]

Isotopes

Main article: Isotopes of carbon

NMR experiments is done with the isotope ¹³C.

radiocarbon dating, discovered in 1949, which has been used extensively to determine the age of carbonaceous materials with ages up to about 40,000 years.^[21][22]

There are 15 known isotopes of carbon and the shortest-lived of these is ⁸C which decays through density.^[24]

Allotropes

Main article: Allotropes of carbon

The carbon nanofoam.^[32]

The activated carbon.

At normal pressures carbon takes the form of metals. The delocalization also accounts for the energetic stability of graphite over diamond at room temperature.

 

At very high pressures carbon forms the more compact allotrope crystal lattice.^[31]

nanomaterials. The name "fullerene" is given after Richard Buckminster Fuller, developer of some geodesic domes,^{[citation needed]} which resemble the structure of fullerenes. The buckyballs are fairly large molecules formed completely of carbon bonded trigonally, forming spheroids (the best-known and simplest is the soccerball-shaped structure C₆₀ buckminsterfullerene).^[14] Carbon nanotubes are structurally similar to buckyballs, except that each atom is bonded trigonally in a curved sheet that forms a hollow cylinder.^[25][26] Nanobuds were first published in 2007 and are hybrid bucky tube/buckyball materials (buckyballs are covalently bonded to the outer wall of a nanotube) that combine the properties of both in a single structure.^[27]

Of the other discovered allotropes, glassy carbon contains a high proportion of closed porosity.^[16] But unlike normal graphite, the graphitic layers are not stacked like pages in a book, but have a more random arrangement.

Characteristics

Carbon exhibits remarkable properties, some paradoxical. Different forms include the hardest naturally occurring substance (rhenium. Although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature.

Carbon compounds form the basis of all life on Earth and the exothermic reaction is used in the iron and steel industry to control the carbon content of steel:
Fe₃O₄ + 4C_(s) → 3Fe_(s) + 4CO_(g)
with carbon disulfide and with steam in the coal-gas reaction
C_(s) + H₂O_(g) → CO_(g) + H_2(g).
Carbon combines with some metals at high temperatures to form metallic carbides, such as the iron carbide abrasive and for making hard tips for cutting tools.  

The system of carbon allotropes spans a range of extremes:

Synthetic diamond nanorods are the hardest materials known.	Graphite is one of the softest materials known.
Diamond is the ultimate abrasive.	Graphite is a very good lubricant.
Diamond is an excellent electrical insulator.	Graphite is a conductor of electricity.
Diamond is the best known thermal conductor	Some forms of graphite are used for thermal insulation (i.e. firebreaks and heatshields)
Diamond is highly transparent.	Graphite is opaque.
Diamond crystallizes in the cubic system.	Graphite crystallizes in the hexagonal system.
Amorphous carbon is completely isotropic.	Carbon nanotubes are among the most anisotropic materials ever produced.

Occurrence

   

Carbon is the Sun, stars, comets, and in the atmospheres of most planets. Some meteorites contain microscopic diamonds that were formed when the solar system was still a protoplanetary disk. Microscopic diamonds may also be formed by the intense pressure and high temperature at the sites of meteorite impacts.^[35]

 

In combination with other elements, carbon is found in the Earth's atmosphere (in quantities of approximately 810 gigatonnes) and dissolved in all water bodies (approximately 36000 gigatonnes). Around 1900 gigatonnes are present in the biosphere. Hydrocarbons (such as coal, petroleum, and natural gas) contain carbon as well — coal "reserves" (not "resources") amount to around 1000 gigatonnes, and oil reserves around 150 gigatonnes. With smaller amounts of marble etc.).

Coal is a significant commercial source of mineral carbon; anthracite containing 92-98% carbon^{[citation needed]} and the largest source (4000 Gt, or 80% of coal, gas and oil reserves) of carbon in a form suitable for use as fuel.^[36]

Graphite is found in large quantities in New York and Texas, the United States, Russia, Mexico, Greenland, and India.

Natural diamonds occur in the mineral volcanic "necks," or "pipes". Most diamond deposits are in Africa, notably in South Africa, Namibia, Botswana, the Republic of the Congo, and Sierra Leone. There are also deposits in Arkansas, Canada, the Russian Arctic, Brazil and in Northern and Western Australia.

Carbon is also found in abundance in the Sun, stars, comets, and atmospheres of most planets. Diamonds are now also being recovered from the ocean floor off the Cape of Good Hope. About 30% of all industrial diamonds used in the U.S. are now made synthetically.

According to studies from the Massachusetts Institute of Technology, an estimate of the global carbon budget is:^{[citation needed]}

Biosphere, oceans, atmosphere
0.45 x 1018 moles)
Crust
Organic carbon	13.2 x 1018 kg
Carbonates	62.4 x 1018 kg
Mantle
1200 x 1018 kg

Carbon-14 is formed in upper layers of the troposphere and the stratosphere, at altitudes of 9–15 km, by a reaction that is precipitated by cosmic rays. Thermal neutrons are produced that collide with the nuclei of nitrogen-14, forming carbon-14 and a proton.

Formation in stars

Formation of the carbon atomic nucleus requires a nearly simultaneous triple collision of triple-alpha process. In order to be available for formation of life as we know it, this carbon must then later be scattered into space as dust, in supernovae explosions, as part of the material which later forms second- and third-generation star systems which have planets accreted from such dust. The Solar System is one such third-generation star system.

One of the fusion mechanisms powering stars is the carbon-nitrogen cycle.

Rotational transitions of various isotopic forms of carbon monoxide (e.g. ¹²CO, ¹³CO, and C¹⁸O) are detectable in the submillimeter regime, and are used in the study of newly forming stars in molecular clouds.

Carbon cycle

Main article: Carbon cycle

  Under terrestrial conditions, conversion of one element to another is very rare. Therefore, the amount of carbon on Earth is effectively constant. Thus, processes that use carbon must obtain it somewhere and dispose of it somewhere else. The paths that carbon follows in the environment make up the carbon fixation. Some of this biomass is eaten by animals, whereas some carbon is exhaled by animals as carbon dioxide. The carbon cycle is considerably more complicated than this short loop; for example, some carbon dioxide is dissolved in the oceans; dead plant or animal matter may become petroleum or coal, which can burn with the release of carbon, should bacteria not consume it.

Production

Please help improve this article by expanding this section. See talk page for details. Please remove this message once the section has been expanded.

Graphite Production

Commercially-viable natural deposits of graphite occur in many parts of the world, but the most important sources economically are in South Korea and Austria. Graphite deposits are of metamorphic origin, found in association with metre or more in thickness. Deposits of graphite in Borrowdale, Cumberland, England were at first of sufficient size and purity that, until the 1800s, pencils were made simply by sawing blocks of natural graphite into strips before encasing the strips in wood. Today, smaller deposits of graphite are obtained by crushing the parent rock and floating the lighter graphite out on water.

Compounds

Main article: Carbon-containing compounds

The most prominent oxide of carbon is Carbon disulfide (CS₂) is similar.

The other common oxide is carbon trioxide (CO₃).^[43][44]

With reactive diamond.

Organic compounds

Main article: Organic compound

  Carbon has the ability to form very long chains with interconnecting C-C bonds. This property is called catenation. Carbon-carbon bonds are strong, and stable.^{[citation needed]} This property allows carbon to form an almost infinite number of compounds; in fact, there are more known carbon-containing compounds than all the compounds of the other chemical elements combined except those of hydrogen (because almost all organic compounds contain hydrogen too).

The simplest form of an organic molecule is the functional groups all affect the properties of organic molecules. By IUPAC's definition, all the other organic compounds are functionalized compounds of hydrocarbons.^{[citation needed]}

 

Carbon occurs in all organic life and is the basis of fossil fuels.

When combined with oxygen and hydrogen, carbon can form many groups of important biological compounds including sugars, adenosine triphosphate (ATP), the most important energy-transfer molecules in all living cells.

Applications

           

Carbon is essential to all known living systems, and without it life as we know it could not exist (see alternative biochemistry). The major economic use of carbon not in living or formerly-living material (such as food and wood) is in the form of hydrocarbons, most notably the Plastics are made from synthetic carbon polymers, often with oxygen and nitrogen atoms included at regular intervals in the main polymer chain. The raw materials for many of these synthetic substances come from crude oil.

The uses of carbon and its compounds are extremely varied. It can form neutron moderator in nuclear reactors.

specific tensile strength than steel.^{[citation needed]}

textiles and leather, and almost all of the interior surfaces in the built environment other than glass, stone and metal.

Precautions

Pure carbon has extremely low toxicity and can be handled and even ingested safely in the form of graphite or charcoal. It is resistant to dissolution or chemical attack, even in the acidic contents of the digestive tract, for example. Consequently if it gets into body tissues it is likely to remain there indefinitely. carbon black) in large quantities can be dangerous, irritating lung tissues and causing the congestive lung disease coalworker's pneumoconiosis. Similarly, diamond dust used as an abrasive can do harm if ingested or inhaled. Microparticles of carbon are produced in diesel engine exhaust fumes, and may accumulate in the lungs^[47] In these examples, the harmful effects may result from contamination of the carbon particles, with organic chemicals or heavy metals for example, rather than from the carbon itself.

Carbon may also burn vigorously and brightly in the presence of air at high temperatures, as in the Windscale fire, which was caused by sudden release of stored Wigner energy in the graphite core. Large accumulations of coal, which have remained inert for millennia in the absence of oxygen, may spontaneously combust when exposed to air, for example in coal mine waste tips.

The great variety of carbon compounds include such lethal poisons as protein.

See also

References

• On Graphite Transformations at High Temperature and Pressure Induced by Absorption of the LHC Beam, J.M. Zazula, 1997