Carbon - An Introduction

8/7/2019 Carbon - An Introduction

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Carbon ( /k r b n/) is thechemical elementwithsymbolC and atomic number6. As a member

ofgroup 14 on the periodic table, it isnonmetallic and tetravalentmaking four electrons available to

form covalentchemical bonds. There are three naturally occurring isotopes, with12C and13C being stable,

while14C is radioactive, decaying with a half-life of about 5730 years.[9]Carbon is one of the few elements

known since antiquity.[10][11] The name "carbon" comes from Latin languagecarbo, coal.

There are several allotropes of carbon of which the best known aregraphite, diamond, andamorphous

carbon.[12] The physical propertiesof carbon vary widely with the allotropic form. For example, diamond is

highly transparent, while graphite isopaque and black. Diamond is among the hardest materials known,

while graphite is soft enough to form a streak on paper (hence its name, from the Greek word "to write").

Diamond has a very lowelectrical conductivity, while graphite is a very good conductor. Under normal

conditions, diamond has the highest thermal conductivity ofall known materials. All the allotropic forms

are solids under normal conditions but graphite is the mostthermodynamically stable.

All forms of carbon are highly stable, requiring high temperature to react even with oxygen. The most

common oxidation state of carbon ininorganic compounds is +4, while +2 is found incarbon

monoxideand othertransition metalcarbonyl complexes. The largest sources of inorganic carbon

are limestones, dolomitesand carbon dioxide, but significant quantities occur in organic deposits

ofcoal,peat, oilandmethane clathrates. Carbon forms more compounds than any other element, with

almost ten million pure organic compounds described to date, which in turn are a tiny fraction of such

compounds that are theoretically possible under standard conditions.[13]

Carbon is the 15thmost abundant element in the Earth's crust, and the fourth most abundant element in

the universe by massafterhydrogen,helium, and oxygen. It is present in all knownlifeforms, and in the

human body carbon is the second most abundant element by mass (about 18.5%) after oxygen.[14] This

abundance, together with the unique diversity oforganic compoundsand their unusual polymer-forming

ability at the temperatures commonly encountered onEarth, make this element the chemical basis of all

known life.

Contents

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1 Characteristics

o 1.1 Allotropes

o 1.2 Occurrence

o 1.3 Isotopes

o 1.4 Formation in stars

o 1.5 Carbon cycle
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English#Keyhttp://en.wikipedia.org/wiki/Wikipedia:IPA_for_English#Keyhttp://en.wikipedia.org/wiki/Wikipedia:IPA_for_English#Keyhttp://en.wikipedia.org/wiki/Wikipedia:IPA_for_English#Keyhttp://en.wikipedia.org/wiki/Wikipedia:IPA_for_English#Keyhttp://en.wikipedia.org/wiki/Wikipedia:IPA_for_Englishhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Chemical_symbolhttp://en.wikipedia.org/wiki/Atomic_numberhttp://en.wikipedia.org/wiki/Group_14http://en.wikipedia.org/wiki/Periodic_tablehttp://en.wikipedia.org/wiki/Nonmetalhttp://en.wikipedia.org/wiki/Tetravalencehttp://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Isotopeshttp://en.wikipedia.org/wiki/Carbon-12http://en.wikipedia.org/wiki/Carbon-13http://en.wikipedia.org/wiki/Carbon-14http://en.wikipedia.org/wiki/Radioactivehttp://en.wikipedia.org/wiki/Half-lifehttp://en.wikipedia.org/wiki/Carbon#cite_note-isotopes-8http://en.wikipedia.org/wiki/Discoveries_of_the_chemical_elementshttp://en.wikipedia.org/wiki/Discoveries_of_the_chemical_elementshttp://en.wikipedia.org/wiki/Carbon#cite_note-9http://en.wikipedia.org/wiki/Carbon#cite_note-D2-10http://en.wikipedia.org/wiki/Latin_languagehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Allotropes_of_carbonhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-therm_prop-11http://en.wikipedia.org/wiki/Physical_propertieshttp://en.wikipedia.org/wiki/Transparency_(optics)http://en.wikipedia.org/wiki/Opacity_(optics)http://en.wikipedia.org/wiki/Electrical_conductivityhttp://en.wikipedia.org/wiki/Electrical_conductorhttp://en.wikipedia.org/wiki/Thermal_conductivityhttp://en.wikipedia.org/wiki/List_of_thermal_conductivitieshttp://en.wikipedia.org/wiki/Thermodynamic_equilibriumhttp://en.wikipedia.org/wiki/Oxidation_statehttp://en.wikipedia.org/wiki/Inorganic_compoundshttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Transition_metalhttp://en.wikipedia.org/wiki/Metal_carbonylhttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Peathttp://en.wikipedia.org/wiki/Petroleumhttp://en.wikipedia.org/wiki/Methane_clathratehttp://en.wikipedia.org/wiki/Chemical_compoundhttp://en.wikipedia.org/wiki/Organic_compoundhttp://en.wikipedia.org/wiki/Carbon#cite_note-lanl-12http://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth's_crusthttp://en.wikipedia.org/wiki/Abundance_of_the_chemical_elementshttp://en.wikipedia.org/wiki/Abundance_of_the_chemical_elementshttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Lifehttp://en.wikipedia.org/wiki/Carbon#cite_note-13http://en.wikipedia.org/wiki/Organic_compoundshttp://en.wikipedia.org/wiki/Earthhttp://en.wikipedia.org/wiki/Carbonhttp://en.wikipedia.org/wiki/Carbon#Characteristicshttp://en.wikipedia.org/wiki/Carbon#Allotropeshttp://en.wikipedia.org/wiki/Carbon#Occurrencehttp://en.wikipedia.org/wiki/Carbon#Isotopeshttp://en.wikipedia.org/wiki/Carbon#Formation_in_starshttp://en.wikipedia.org/wiki/Carbon#Carbon_cyclehttp://en.wikipedia.org/wiki/Wikipedia:IPA_for_English


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2 Compounds

o 2.1 Organic

compounds

o 2.2 Inorganic

compounds

o 2.3 Organometallic

compounds

3 History and etymology

4 Production

o 4.1 Graphite

o 4.2 Diamond

5 Applications

o 5.1 Diamonds

6 Precautions

7 See also

8 Bonding to Carbon

9 References

10 External links

Characteristics

Theoretically predicted phase diagram of carbon

The different forms orallotropes of carbon (see below) include the hardest naturally occurring

substance, diamond, and also one of the softest known substances, graphite. Moreover, it has an affinity

forbonding with other small atoms, including other carbon atoms, and is capable of forming multiple

stablecovalent bonds with such atoms. As a result, carbon is known to form almost ten million different

compounds; the large majority of allchemical compounds.[13]Carbon also has the
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highest meltingandsublimationpoint of all elements. At atmospheric pressure it has no melting point as

its triple point is at 10.8 0.2 MPa and 4600 300 K, [2][3]so it sublimates at about 3900 K.[15][16]

Carbon sublimes in a carbon arc which has a temperature of about 5800 K. Thus, irrespective of its

allotropic form, carbon remains solid at higher temperatures than the highest melting point metals such

astungsten orrhenium. 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 known life on Earth, and the carbon-nitrogen cycle provides

some of the energy produced by theSun and otherstars. Although it forms an extraordinary variety of

compounds, most forms of carbon are comparatively unreactive under normal conditions. At standard

temperature and pressure, it resists all but the strongest oxidizers. It does not react with sulfuric

acid,hydrochloric acid,chlorine or any alkalis. At elevated temperatures carbon reacts with oxygen to form

carbon oxides, and will reduce such metal oxides as iron oxide to the metal. This exothermic reaction is

used in the iron and steel industry to control the carbon content of steel:

Fe3O4 + 4 C(s) 3 Fe(s) + 4 CO(g)

withsulfurto form carbon disulfide and with steam in the coal-gas reaction:

C(s) + H2O(g) CO(g) + H2(g).

Carbon combines with some metals at high temperatures to form metallic carbides, such as

the iron carbide cementite in steel, andtungsten carbide, widely used as anabrasiveand for

making hard tips for cutting tools.

As of 2009,graphene appears to be the strongest material ever tested.[17] However, the

process of separating it from graphite will require some technological development before it is

economical enough to be used in industrial processes.[18]

The system of carbon allotropes spans a range of extremes:

Synthetic nanocrystalline diamondis the hardest material known.Graphite is one of the softest materials

known.

Diamond is the ultimateabrasive. Graphite is a very goodlubricant.

Diamond is an excellent electricalinsulator. Graphite is aconductorof electricity.

Diamond is the best known naturally occurringthermal conductorSome forms of graphite are used

forthermal insulation(i.e. firebreaks
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and heat shields)

Diamond is highly transparent. Graphite isopaque.

Diamond crystallizes in the cubic system.Graphite crystallizes in the hexagonal

system.

Amorphous carbon is completelyisotropic.

Carbon nanotubes are among the

most anisotropic materials ever

produced.

Allotropes

Main article:Allotropes of carbon

Atomic carbon is a very short-lived species and, therefore, carbon is stabilized in various multi-

atomic structures with different molecular configurations calledallotropes. The three relatively

well-known allotropes of carbon are amorphous carbon,graphite, and diamond. Once

considered exotic,fullerenes are nowadays commonly synthesized and used in research; they

includebuckyballs,[19][20]carbon nanotubes,[21]carbon nanobuds[22] andnanofibers.[23][24]Several

other exotic allotropes have also been discovered, such aslonsdaleite,[25]glassy carbon,

[26]carbon nanofoam[27] and linear acetylenic carbon.[28]

The amorphous form is an assortment of carbon atoms in a non-crystalline, irregular,glassy state, which is essentially graphitebut not held in a crystalline macrostructure. It is

present as a powder, and is the main constituent of substances such

ascharcoal,lampblack (soot) andactivated carbon.

At normal pressures carbon takes the form ofgraphite, in which each atom is bonded

trigonally to three others in a plane composed of fusedhexagonal rings, just like those

inaromatic hydrocarbons. The resulting network is 2-dimensional, and the resulting flat

sheets are stacked and loosely bonded through weak van der Waals forces. This gives

graphite its softness and its cleaving properties (the sheets slip easily past one another).

Because of the delocalization of one of the outer electrons of each atom to form a -cloud,

graphite conducts electricity, but only in the plane of each covalently bondedsheet. This

results in a lower bulk electrical conductivityfor carbon than for most metals. The

delocalization also accounts for the energetic stability of graphite over diamond at room

temperature.
http://en.wikipedia.org/wiki/Opacity_(optics)http://en.wikipedia.org/wiki/Opacity_(optics)http://en.wikipedia.org/wiki/Opacity_(optics)http://en.wikipedia.org/wiki/Cubic_(crystal_system)http://en.wikipedia.org/wiki/Hexagonal_(crystal_system)http://en.wikipedia.org/wiki/Hexagonal_(crystal_system)http://en.wikipedia.org/wiki/Hexagonal_(crystal_system)http://en.wikipedia.org/wiki/Isotropichttp://en.wikipedia.org/wiki/Isotropichttp://en.wikipedia.org/wiki/Isotropichttp://en.wikipedia.org/wiki/Anisotropichttp://en.wikipedia.org/wiki/Allotropes_of_carbonhttp://en.wikipedia.org/wiki/Atomic_carbonhttp://en.wikipedia.org/wiki/Allotropeshttp://en.wikipedia.org/wiki/Allotropeshttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Buckyballhttp://en.wikipedia.org/wiki/Buckyballhttp://en.wikipedia.org/wiki/Buckyballhttp://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes-19http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes-19http://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes2-20http://en.wikipedia.org/wiki/Carbon_nanobudhttp://en.wikipedia.org/wiki/Carbon_nanobudhttp://en.wikipedia.org/wiki/Carbon_nanobudhttp://en.wikipedia.org/wiki/Carbon#cite_note-nanobuds-21http://en.wikipedia.org/wiki/Carbon#cite_note-nanobuds-21http://en.wikipedia.org/wiki/Carbon_nanofibershttp://en.wikipedia.org/wiki/Carbon_nanofibershttp://en.wikipedia.org/wiki/Carbon_nanofibershttp://en.wikipedia.org/wiki/Carbon#cite_note-22http://en.wikipedia.org/wiki/Carbon#cite_note-23http://en.wikipedia.org/wiki/Carbon#cite_note-23http://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Carbon#cite_note-lonsdaletite-24http://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-glassy_carbon-25http://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Carbon#cite_note-26http://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Linear_acetylenic_carbonhttp://en.wikipedia.org/wiki/Linear_acetylenic_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-LAC-27http://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Charcoalhttp://en.wikipedia.org/wiki/Charcoalhttp://en.wikipedia.org/wiki/Charcoalhttp://en.wikipedia.org/wiki/Lampblackhttp://en.wikipedia.org/wiki/Soothttp://en.wikipedia.org/wiki/Activated_carbonhttp://en.wikipedia.org/wiki/Activated_carbonhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Hexagonhttp://en.wikipedia.org/wiki/Hexagonhttp://en.wikipedia.org/wiki/Aromatic_hydrocarbonhttp://en.wikipedia.org/wiki/Aromatic_hydrocarbonhttp://en.wikipedia.org/wiki/Van_der_Waals_forcehttp://en.wikipedia.org/wiki/Cleavage_(crystal)http://en.wikipedia.org/wiki/Delocalized_electronhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Electrical_conductivityhttp://en.wikipedia.org/wiki/Electrical_conductivityhttp://en.wikipedia.org/wiki/Metalshttp://en.wikipedia.org/wiki/Opacity_(optics)http://en.wikipedia.org/wiki/Cubic_(crystal_system)http://en.wikipedia.org/wiki/Hexagonal_(crystal_system)http://en.wikipedia.org/wiki/Hexagonal_(crystal_system)http://en.wikipedia.org/wiki/Isotropichttp://en.wikipedia.org/wiki/Anisotropichttp://en.wikipedia.org/wiki/Allotropes_of_carbonhttp://en.wikipedia.org/wiki/Atomic_carbonhttp://en.wikipedia.org/wiki/Allotropeshttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Buckyballhttp://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes-19http://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes2-20http://en.wikipedia.org/wiki/Carbon_nanobudhttp://en.wikipedia.org/wiki/Carbon#cite_note-nanobuds-21http://en.wikipedia.org/wiki/Carbon_nanofibershttp://en.wikipedia.org/wiki/Carbon#cite_note-22http://en.wikipedia.org/wiki/Carbon#cite_note-23http://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Carbon#cite_note-lonsdaletite-24http://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-glassy_carbon-25http://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Carbon#cite_note-26http://en.wikipedia.org/wiki/Linear_acetylenic_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-LAC-27http://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Charcoalhttp://en.wikipedia.org/wiki/Lampblackhttp://en.wikipedia.org/wiki/Soothttp://en.wikipedia.org/wiki/Activated_carbonhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Hexagonhttp://en.wikipedia.org/wiki/Aromatic_hydrocarbonhttp://en.wikipedia.org/wiki/Van_der_Waals_forcehttp://en.wikipedia.org/wiki/Cleavage_(crystal)http://en.wikipedia.org/wiki/Delocalized_electronhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Electrical_conductivityhttp://en.wikipedia.org/wiki/Metals


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Some allotropes of carbon: a) diamond; b)graphite; c)lonsdaleite; df) fullerenes (C60,

C540, C70); g)amorphous carbon; h) carbon nanotube.

At very high pressures carbon forms the more compact allotrope diamond, having nearly

twice the density of graphite. Here, each atom is bonded tetrahedrallyto four others, thus

making a 3-dimensional network of puckered six-membered rings of atoms. Diamond hasthe same cubic structure as silicon and germaniumand because of the strength of the

carbon-carbonbonds, it is the hardest naturally occurring substance in terms of resistance

to scratching. Contrary to the popular belief that"diamonds are forever", they are in fact

thermodynamically unstable under normal conditions and transform intographite.[12]But

due to a high activation energy barrier, the transition into graphite is so extremely slow at

room temperature as to be unnoticeable.

Under some conditions, carbon crystallizes as lonsdaleite. This form has

ahexagonalcrystallattice where all atoms are covalently bonded. Therefore, all properties

of lonsdaleite are close to those of diamond.[25]

Fullerenes have a graphite-like structure, but instead of purely hexagonal packing, they

also contain pentagons (or even heptagons) of carbon atoms, which bend the sheet into

spheres, ellipses or cylinders. The properties of fullerenes (split

intobuckyballs,buckytubes and nanobuds) have not yet been fully analyzed and represent

an intense area of research innanomaterials. The names "fullerene"and "buckyball"are
http://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Tetrahedronhttp://en.wikipedia.org/wiki/Tetrahedronhttp://en.wikipedia.org/wiki/Cubic_crystal_systemhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Mohs_scalehttp://en.wikipedia.org/wiki/Mohs_scalehttp://en.wikipedia.org/wiki/Diamonds_Are_Forever_(novel)http://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Carbon#cite_note-therm_prop-11http://en.wikipedia.org/wiki/Carbon#cite_note-therm_prop-11http://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Hexagonalhttp://en.wikipedia.org/wiki/Hexagonalhttp://en.wikipedia.org/wiki/Hexagonalhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Carbon#cite_note-lonsdaletite-24http://en.wikipedia.org/wiki/Carbon#cite_note-lonsdaletite-24http://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Hexagonal_crystal_systemhttp://en.wikipedia.org/wiki/Buckyballhttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Nanobudhttp://en.wikipedia.org/wiki/Nanobudhttp://en.wikipedia.org/wiki/Nanomaterialshttp://en.wikipedia.org/wiki/File:Eight_Allotropes_of_Carbon.pnghttp://en.wikipedia.org/wiki/File:Eight_Allotropes_of_Carbon.pnghttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Tetrahedronhttp://en.wikipedia.org/wiki/Cubic_crystal_systemhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Chemical_bondhttp://en.wikipedia.org/wiki/Mohs_scalehttp://en.wikipedia.org/wiki/Mohs_scalehttp://en.wikipedia.org/wiki/Diamonds_Are_Forever_(novel)http://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Carbon#cite_note-therm_prop-11http://en.wikipedia.org/wiki/Lonsdaleitehttp://en.wikipedia.org/wiki/Hexagonalhttp://en.wikipedia.org/wiki/Crystalhttp://en.wikipedia.org/wiki/Carbon#cite_note-lonsdaletite-24http://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Hexagonal_crystal_systemhttp://en.wikipedia.org/wiki/Buckyballhttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Nanobudhttp://en.wikipedia.org/wiki/Nanomaterials


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given afterRichard Buckminster Fuller, popularizer ofgeodesic domes, 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 C60buckminsterfullerene).[19]Carbon nanotubes are structurally

similar to buckyballs, except that each atom is bonded trigonally in a curved sheet that

forms a hollow cylinder.[20][21] 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.[22]

Of the other discovered allotropes,carbon nanofoamis aferromagnetic allotrope

discovered in 1997. It consists of a low-density cluster-assembly of carbon atoms strung

together in a loose three-dimensional web, in which the atoms are bonded trigonally in six-

and seven-membered rings. It is among the lightest known solids, with a density of about

2 kg/m3

.[29]

Similarly, glassy carbon contains a high proportion of closedporosity.[26]

Butunlike normal graphite, the graphitic layers are not stacked like pages in a book, but have

a more random arrangement. Linear acetylenic carbon[28] has the chemical structure[28] -

(C:::C)n-. Carbon in this modification is linear with sporbital hybridization, and is

apolymerwith alternating single and triple bonds. This type of carbyne is of considerable

interest to nanotechnologyas its Young's modulus is forty times that of the hardest known

material - diamond.[30]

Occurrence

Graphite ore
http://en.wikipedia.org/wiki/Buckminster_Fullerhttp://en.wikipedia.org/wiki/Buckminster_Fullerhttp://en.wikipedia.org/wiki/Geodesic_domehttp://en.wikipedia.org/wiki/Geodesic_domehttp://en.wikipedia.org/wiki/Geodesic_domehttp://en.wikipedia.org/wiki/Spheroidhttp://en.wikipedia.org/wiki/Buckminsterfullerenehttp://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Cylinder_(geometry)http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes-19http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes-19http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes2-20http://en.wikipedia.org/wiki/Carbon#cite_note-nanobuds-21http://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Ferromagnetichttp://en.wikipedia.org/wiki/Ferromagnetichttp://en.wikipedia.org/wiki/Carbon#cite_note-28http://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Porosityhttp://en.wikipedia.org/wiki/Porosityhttp://en.wikipedia.org/wiki/Carbon#cite_note-glassy_carbon-25http://en.wikipedia.org/wiki/Linear_acetylenic_carbonhttp://en.wikipedia.org/wiki/Linear_acetylenic_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-LAC-27http://en.wikipedia.org/wiki/Linear_acetylenic_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-LAC-27http://en.wikipedia.org/wiki/Orbital_hybridizationhttp://en.wikipedia.org/wiki/Orbital_hybridizationhttp://en.wikipedia.org/wiki/Orbital_hybridizationhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Nanotechnologyhttp://en.wikipedia.org/wiki/Nanotechnologyhttp://en.wikipedia.org/wiki/Young's_modulushttp://en.wikipedia.org/wiki/Carbon#cite_note-29http://en.wikipedia.org/wiki/Carbon#cite_note-29http://en.wikipedia.org/wiki/File:GraphiteOreUSGOV.jpghttp://en.wikipedia.org/wiki/File:GraphiteOreUSGOV.jpghttp://en.wikipedia.org/wiki/Buckminster_Fullerhttp://en.wikipedia.org/wiki/Geodesic_domehttp://en.wikipedia.org/wiki/Spheroidhttp://en.wikipedia.org/wiki/Buckminsterfullerenehttp://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Cylinder_(geometry)http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes-19http://en.wikipedia.org/wiki/Carbon#cite_note-nanotubes2-20http://en.wikipedia.org/wiki/Carbon#cite_note-nanobuds-21http://en.wikipedia.org/wiki/Carbon_nanofoamhttp://en.wikipedia.org/wiki/Ferromagnetichttp://en.wikipedia.org/wiki/Carbon#cite_note-28http://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Porosityhttp://en.wikipedia.org/wiki/Carbon#cite_note-glassy_carbon-25http://en.wikipedia.org/wiki/Linear_acetylenic_carbonhttp://en.wikipedia.org/wiki/Carbon#cite_note-LAC-27http://en.wikipedia.org/wiki/Carbon#cite_note-LAC-27http://en.wikipedia.org/wiki/Orbital_hybridizationhttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Nanotechnologyhttp://en.wikipedia.org/wiki/Young's_modulushttp://en.wikipedia.org/wiki/Carbon#cite_note-29


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Raw diamond crystal.

"Present day" (1990s) sea surfacedissolved inorganic carbon concentration (from

theGLODAPclimatology)

Carbon is the fourth most abundant chemical elementin the universe by mass after hydrogen,

helium, and oxygen. Carbon is abundant in theSun,stars,comets, and in the atmospheres of

mostplanets. Some meteorites contain microscopic diamonds that were formed whenthe 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.[31]

In combination withoxygen in carbon dioxide, carbon is found in the Earth's atmosphere

(approximately 810 gigatonnes of carbon) and dissolved in all water bodies (approximately

36,000 gigatonnes of carbon). Around 1,900 gigatonnes of carbon are present in

the biosphere.Hydrocarbons (such as coal,petroleum, andnatural gas) contain carbon as well

coal"reserves" (not "resources") amount to around 900 gigatonnes, and oil reservesaround

150 gigatonnes. Proven sources of natural gas are about 175 trillion cubic metres(representing about 105 gigatonnes carbon), but it is estimated that there are also about 900

trillion cubic metres of "unconventional" gas such as shale gas, representing about 540

gigatonnes carbon.[32]

Carbon is a major component in very large masses ofcarbonate rock

(limestone,dolomite, marble etc.).
http://en.wikipedia.org/wiki/Total_inorganic_carbonhttp://en.wikipedia.org/wiki/Global_Ocean_Data_Analysis_Projecthttp://en.wikipedia.org/wiki/Global_Ocean_Data_Analysis_Projecthttp://en.wikipedia.org/wiki/Climatologyhttp://en.wikipedia.org/wiki/Abundance_of_the_chemical_elementshttp://en.wikipedia.org/wiki/Abundance_of_the_chemical_elementshttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Starhttp://en.wikipedia.org/wiki/Comethttp://en.wikipedia.org/wiki/Comethttp://en.wikipedia.org/wiki/Celestial_body's_atmospherehttp://en.wikipedia.org/wiki/Planethttp://en.wikipedia.org/wiki/Planethttp://en.wikipedia.org/wiki/Meteoritehttp://en.wikipedia.org/wiki/Solar_systemhttp://en.wikipedia.org/wiki/Protoplanetary_diskhttp://en.wikipedia.org/wiki/Protoplanetary_diskhttp://en.wikipedia.org/wiki/Carbon#cite_note-30http://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Gigatonnehttp://en.wikipedia.org/wiki/Biospherehttp://en.wikipedia.org/wiki/Hydrocarbonshttp://en.wikipedia.org/wiki/Hydrocarbonshttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Petroleumhttp://en.wikipedia.org/wiki/Petroleumhttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Mineral_resource_classificationhttp://en.wikipedia.org/wiki/Oil_reserveshttp://en.wikipedia.org/wiki/Oil_reserveshttp://en.wikipedia.org/wiki/Shale_gashttp://en.wikipedia.org/wiki/Carbon#cite_note-31http://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Marblehttp://en.wikipedia.org/wiki/File:WOA05_GLODAP_pd_DIC_AYool.pnghttp://en.wikipedia.org/wiki/File:WOA05_GLODAP_pd_DIC_AYool.pnghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/File:Rough_diamond.jpghttp://en.wikipedia.org/wiki/Total_inorganic_carbonhttp://en.wikipedia.org/wiki/Global_Ocean_Data_Analysis_Projecthttp://en.wikipedia.org/wiki/Climatologyhttp://en.wikipedia.org/wiki/Abundance_of_the_chemical_elementshttp://en.wikipedia.org/wiki/Sunhttp://en.wikipedia.org/wiki/Starhttp://en.wikipedia.org/wiki/Comethttp://en.wikipedia.org/wiki/Celestial_body's_atmospherehttp://en.wikipedia.org/wiki/Planethttp://en.wikipedia.org/wiki/Meteoritehttp://en.wikipedia.org/wiki/Solar_systemhttp://en.wikipedia.org/wiki/Protoplanetary_diskhttp://en.wikipedia.org/wiki/Carbon#cite_note-30http://en.wikipedia.org/wiki/Oxygenhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Gigatonnehttp://en.wikipedia.org/wiki/Biospherehttp://en.wikipedia.org/wiki/Hydrocarbonshttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Petroleumhttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Mineral_resource_classificationhttp://en.wikipedia.org/wiki/Oil_reserveshttp://en.wikipedia.org/wiki/Shale_gashttp://en.wikipedia.org/wiki/Carbon#cite_note-31http://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Marble


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Coal is a significant commercial source of mineral carbon;anthracitecontaining 9298%

carbon[33]and the largest source (4,000 Gt, or 80% of coal, gas and oil reserves) of carbon in a

form suitable for use as fuel.[34]

Graphite is found in large quantities in the United States(mostly in New

York and Texas), Russia, Mexico,Greenland, and India.

Natural diamonds occur in the rock kimberlite, found in ancient volcanic"necks," or "pipes".

Most diamond deposits are inAfrica, notably inSouth Africa,Namibia, Botswana, the Republic

of the Congo, and Sierra Leone. There are also deposits in Arkansas, Canada, the

RussianArctic,Brazil and in Northern and Western Australia.

Diamonds are now also being recovered from the ocean floor off the Cape of Good Hope.

However, though diamonds are found naturally, about 30% of all industrial diamonds used in

the U.S. are now made synthetically.

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 bycosmic rays. Thermal neutrons are produced that

collide with the nuclei of nitrogen-14, forming carbon-14 and a proton.

Isotopes

Main article: Isotopes of carbon

Isotopes of carbon are atomic nuclei that contain six protonsplus a number

ofneutrons (varying from 2 to 16). Carbon has two stable, naturally occurring isotopes.[9]The

isotope carbon-12 (

12

C) forms 98.93% of the carbon on Earth, whilecarbon-13(

13

C) forms theremaining 1.07%.[9]The concentration of12C is further increased in biological materials because

biochemical reactions discriminate against 13C.[35]In 1961 theInternational Union of Pure and

Applied Chemistry (IUPAC) adopted the isotopecarbon-12 as the basis foratomic weights.

[36] Identification of carbon inNMRexperiments is done with the isotope 13C.

Carbon-14(14C) is a naturally occurring radioisotopewhich occurs in trace amounts on Earth of

up to 1 part pertrillion (0.0000000001%), mostly confined to the atmosphere and superficial

deposits, particularly ofpeatand other organic materials.[37] This isotope decays by 0.158

MeV- emission. Because of its relatively short half-life of 5730 years, 14C is virtually absent in

ancient rocks, but is created in theupper atmosphere (lowerstratosphere and

uppertroposphere) by interaction ofnitrogenwith cosmic rays.[38] The abundance of14C in

the atmosphereand in living organisms is almost constant, but decreases predictably in their

bodies after death. This principle is used in radiocarbon dating, invented in 1949, which has

been used extensively to determine the age of carbonaceous materials with ages up to about

40,000 years.[39][40]
http://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Anthracitehttp://en.wikipedia.org/wiki/Anthracitehttp://en.wikipedia.org/wiki/Anthracitehttp://en.wikipedia.org/wiki/Carbon#cite_note-32http://en.wikipedia.org/wiki/Carbon#cite_note-32http://en.wikipedia.org/wiki/Carbon#cite_note-33http://en.wikipedia.org/wiki/Carbon#cite_note-33http://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/New_Yorkhttp://en.wikipedia.org/wiki/New_Yorkhttp://en.wikipedia.org/wiki/Texashttp://en.wikipedia.org/wiki/Russiahttp://en.wikipedia.org/wiki/Mexicohttp://en.wikipedia.org/wiki/Greenlandhttp://en.wikipedia.org/wiki/Greenlandhttp://en.wikipedia.org/wiki/Greenlandhttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Kimberlitehttp://en.wikipedia.org/wiki/Volcanohttp://en.wikipedia.org/wiki/Volcanohttp://en.wikipedia.org/wiki/Africahttp://en.wikipedia.org/wiki/Africahttp://en.wikipedia.org/wiki/South_Africahttp://en.wikipedia.org/wiki/Namibiahttp://en.wikipedia.org/wiki/Namibiahttp://en.wikipedia.org/wiki/Botswanahttp://en.wikipedia.org/wiki/Republic_of_the_Congohttp://en.wikipedia.org/wiki/Republic_of_the_Congohttp://en.wikipedia.org/wiki/Republic_of_the_Congohttp://en.wikipedia.org/wiki/Sierra_Leonehttp://en.wikipedia.org/wiki/Arkansashttp://en.wikipedia.org/wiki/Canadahttp://en.wikipedia.org/wiki/Canadahttp://en.wikipedia.org/wiki/Arctichttp://en.wikipedia.org/wiki/Arctichttp://en.wikipedia.org/wiki/Brazilhttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Cape_of_Good_Hopehttp://en.wikipedia.org/wiki/Cosmic_rayhttp://en.wikipedia.org/wiki/Thermal_neutronhttp://en.wikipedia.org/wiki/Isotopes_of_carbonhttp://en.wikipedia.org/wiki/Isotopehttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Protonhttp://en.wikipedia.org/wiki/Protonhttp://en.wikipedia.org/wiki/Neutronhttp://en.wikipedia.org/wiki/Isotopehttp://en.wikipedia.org/wiki/Carbon#cite_note-isotopes-8http://en.wikipedia.org/wiki/Carbon#cite_note-isotopes-8http://en.wikipedia.org/wiki/Carbon-12http://en.wikipedia.org/wiki/Carbon-13http://en.wikipedia.org/wiki/Carbon-13http://en.wikipedia.org/wiki/Carbon-13http://en.wikipedia.org/wiki/Carbon#cite_note-isotopes-8http://en.wikipedia.org/wiki/Carbon#cite_note-34http://en.wikipedia.org/wiki/Carbon#cite_note-34http://en.wikipedia.org/wiki/Carbon#cite_note-34http://en.wikipedia.org/wiki/International_Union_of_Pure_and_Applied_Chemistryhttp://en.wikipedia.org/wiki/International_Union_of_Pure_and_Applied_Chemistryhttp://en.wikipedia.org/wiki/Carbon-12http://en.wikipedia.org/wiki/Carbon-12http://en.wikipedia.org/wiki/Atomic_weighthttp://en.wikipedia.org/wiki/Carbon#cite_note-35http://en.wikipedia.org/wiki/NMRhttp://en.wikipedia.org/wiki/NMRhttp://en.wikipedia.org/wiki/NMRhttp://en.wikipedia.org/wiki/Carbon-14http://en.wikipedia.org/wiki/Carbon-14http://en.wikipedia.org/wiki/Radioisotopehttp://en.wikipedia.org/wiki/Radioisotopehttp://en.wikipedia.org/wiki/Orders_of_magnitude_(numbers)#1012http://en.wikipedia.org/wiki/Orders_of_magnitude_(numbers)#1012http://en.wikipedia.org/wiki/Peathttp://en.wikipedia.org/wiki/Peathttp://en.wikipedia.org/wiki/Carbon#cite_note-36http://en.wikipedia.org/wiki/Beta_decayhttp://en.wikipedia.org/wiki/Beta_decayhttp://en.wikipedia.org/wiki/Beta_decayhttp://en.wikipedia.org/wiki/Beta_decayhttp://en.wikipedia.org/wiki/Beta_decayhttp://en.wikipedia.org/wiki/Half-lifehttp://en.wikipedia.org/wiki/Upper_atmospherehttp://en.wikipedia.org/wiki/Upper_atmospherehttp://en.wikipedia.org/wiki/Stratospherehttp://en.wikipedia.org/wiki/Stratospherehttp://en.wikipedia.org/wiki/Tropospherehttp://en.wikipedia.org/wiki/Tropospherehttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Cosmic_rayhttp://en.wikipedia.org/wiki/Carbon#cite_note-37http://en.wikipedia.org/wiki/Carbon#cite_note-37http://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Radiocarbon_datinghttp://en.wikipedia.org/wiki/Carbon#cite_note-38http://en.wikipedia.org/wiki/Carbon#cite_note-38http://en.wikipedia.org/wiki/Carbon#cite_note-39http://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Anthracitehttp://en.wikipedia.org/wiki/Carbon#cite_note-32http://en.wikipedia.org/wiki/Carbon#cite_note-33http://en.wikipedia.org/wiki/United_Stateshttp://en.wikipedia.org/wiki/New_Yorkhttp://en.wikipedia.org/wiki/New_Yorkhttp://en.wikipedia.org/wiki/Texashttp://en.wikipedia.org/wiki/Russiahttp://en.wikipedia.org/wiki/Mexicohttp://en.wikipedia.org/wiki/Greenlandhttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Kimberlitehttp://en.wikipedia.org/wiki/Volcanohttp://en.wikipedia.org/wiki/Africahttp://en.wikipedia.org/wiki/South_Africahttp://en.wikipedia.org/wiki/Namibiahttp://en.wikipedia.org/wiki/Botswanahttp://en.wikipedia.org/wiki/Republic_of_the_Congohttp://en.wikipedia.org/wiki/Republic_of_the_Congohttp://en.wikipedia.org/wiki/Sierra_Leonehttp://en.wikipedia.org/wiki/Arkansashttp://en.wikipedia.org/wiki/Canadahttp://en.wikipedia.org/wiki/Arctichttp://en.wikipedia.org/wiki/Brazilhttp://en.wikipedia.org/wiki/Australiahttp://en.wikipedia.org/wiki/Cape_of_Good_Hopehttp://en.wikipedia.org/wiki/Cosmic_rayhttp://en.wikipedia.org/wiki/Thermal_neutronhttp://en.wikipedia.org/wiki/Isotopes_of_carbonhttp://en.wikipedia.org/wiki/Isotopehttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Protonhttp://en.wikipedia.org/wiki/Neutronhttp://en.wikipedia.org/wiki/Isotopehttp://en.wikipedia.org/wiki/Carbon#cite_note-isotopes-8http://en.wikipedia.org/wiki/Carbon-12http://en.wikipedia.org/wiki/Carbon-13http://en.wikipedia.org/wiki/Carbon#cite_note-isotopes-8http://en.wikipedia.org/wiki/Carbon#cite_note-34http://en.wikipedia.org/wiki/International_Union_of_Pure_and_Applied_Chemistryhttp://en.wikipedia.org/wiki/International_Union_of_Pure_and_Applied_Chemistryhttp://en.wikipedia.org/wiki/Carbon-12http://en.wikipedia.org/wiki/Atomic_weighthttp://en.wikipedia.org/wiki/Carbon#cite_note-35http://en.wikipedia.org/wiki/NMRhttp://en.wikipedia.org/wiki/Carbon-14http://en.wikipedia.org/wiki/Radioisotopehttp://en.wikipedia.org/wiki/Orders_of_magnitude_(numbers)#1012http://en.wikipedia.org/wiki/Peathttp://en.wikipedia.org/wiki/Carbon#cite_note-36http://en.wikipedia.org/wiki/Beta_decayhttp://en.wikipedia.org/wiki/Half-lifehttp://en.wikipedia.org/wiki/Upper_atmospherehttp://en.wikipedia.org/wiki/Stratospherehttp://en.wikipedia.org/wiki/Tropospherehttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Cosmic_rayhttp://en.wikipedia.org/wiki/Carbon#cite_note-37http://en.wikipedia.org/wiki/Atmospherehttp://en.wikipedia.org/wiki/Radiocarbon_datinghttp://en.wikipedia.org/wiki/Carbon#cite_note-38http://en.wikipedia.org/wiki/Carbon#cite_note-39


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There are 15 known isotopes of carbon and the shortest-lived of these is 8C which decays

through proton emissionandalpha decayand has a half-life of 1.98739x1021s.[41]The

exotic19C exhibits anuclear halo, which means itsradius is appreciably larger than would be

expected if the nucleuswere a sphereof constant density.[42]

Formation in stars

Main articles: Triple-alpha processandCNO cycle

Formation of the carbon atomic nucleus requires a nearly simultaneous triple collision ofalpha

particles(helium nuclei) within the core of agiantorsupergiantstar. This happens in

conditions of > 100 megakelvin temperature and helium concentration that the rapid expansion

and cooling of the early universe prohibited, and therefore no significant carbon was created

during the Big Bang. Instead, the interiors of stars in thehorizontal branchtransform three

helium nuclei into carbon by means of this 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,insupernovaexplosions, as part of the material which later forms second, third-generation star

systems which have planets accreted from such dust. TheSolar System is one such third-

generation starsystem.

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 thesubmillimeterregime, and are used in the study ofnewly forming

stars in molecular clouds.

Carbon cycleMain article: Carbon cycle

Diagram of the carbon cycle. The black numbers indicate how much carbon is stored in

various reservoirs, in billions of tons ("GtC" stands for gigatons of carbon; figures are circa
http://en.wikipedia.org/wiki/Proton_emissionhttp://en.wikipedia.org/wiki/Proton_emissionhttp://en.wikipedia.org/wiki/Alpha_decayhttp://en.wikipedia.org/wiki/Alpha_decayhttp://en.wikipedia.org/wiki/Alpha_decayhttp://en.wikipedia.org/wiki/Secondhttp://en.wikipedia.org/wiki/Carbon#cite_note-40http://en.wikipedia.org/wiki/Carbon#cite_note-40http://en.wikipedia.org/wiki/Nuclear_halohttp://en.wikipedia.org/wiki/Nuclear_halohttp://en.wikipedia.org/wiki/Radiushttp://en.wikipedia.org/wiki/Radiushttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Spherehttp://en.wikipedia.org/wiki/Spherehttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Carbon#cite_note-41http://en.wikipedia.org/wiki/Carbon#cite_note-41http://en.wikipedia.org/wiki/Triple-alpha_processhttp://en.wikipedia.org/wiki/Triple-alpha_processhttp://en.wikipedia.org/wiki/CNO_cyclehttp://en.wikipedia.org/wiki/CNO_cyclehttp://en.wikipedia.org/wiki/Alpha_particlehttp://en.wikipedia.org/wiki/Alpha_particlehttp://en.wikipedia.org/wiki/Alpha_particlehttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Giant_starhttp://en.wikipedia.org/wiki/Giant_starhttp://en.wikipedia.org/wiki/Giant_starhttp://en.wikipedia.org/wiki/Supergianthttp://en.wikipedia.org/wiki/Supergianthttp://en.wikipedia.org/wiki/Big_Banghttp://en.wikipedia.org/wiki/H-R_diagramhttp://en.wikipedia.org/wiki/H-R_diagramhttp://en.wikipedia.org/wiki/H-R_diagramhttp://en.wikipedia.org/wiki/Triple-alpha_processhttp://en.wikipedia.org/wiki/Triple-alpha_processhttp://en.wikipedia.org/wiki/Supernovaehttp://en.wikipedia.org/wiki/Supernovaehttp://en.wikipedia.org/wiki/Supernovaehttp://en.wikipedia.org/wiki/Solar_Systemhttp://en.wikipedia.org/wiki/Solar_Systemhttp://en.wikipedia.org/wiki/Metallicityhttp://en.wikipedia.org/wiki/Metallicityhttp://en.wikipedia.org/wiki/Carbon-nitrogen_cyclehttp://en.wikipedia.org/wiki/Submillimetre_astronomyhttp://en.wikipedia.org/wiki/Submillimetre_astronomyhttp://en.wikipedia.org/wiki/Submillimetre_astronomyhttp://en.wikipedia.org/wiki/Star_formationhttp://en.wikipedia.org/wiki/Star_formationhttp://en.wikipedia.org/wiki/Star_formationhttp://en.wikipedia.org/wiki/Molecular_cloudshttp://en.wikipedia.org/wiki/Carbon_cyclehttp://en.wikipedia.org/wiki/File:Carbon_cycle-cute_diagram.jpeghttp://en.wikipedia.org/wiki/File:Carbon_cycle-cute_diagram.jpeghttp://en.wikipedia.org/wiki/Proton_emissionhttp://en.wikipedia.org/wiki/Alpha_decayhttp://en.wikipedia.org/wiki/Secondhttp://en.wikipedia.org/wiki/Carbon#cite_note-40http://en.wikipedia.org/wiki/Nuclear_halohttp://en.wikipedia.org/wiki/Radiushttp://en.wikipedia.org/wiki/Atomic_nucleushttp://en.wikipedia.org/wiki/Spherehttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Carbon#cite_note-41http://en.wikipedia.org/wiki/Triple-alpha_processhttp://en.wikipedia.org/wiki/CNO_cyclehttp://en.wikipedia.org/wiki/Alpha_particlehttp://en.wikipedia.org/wiki/Alpha_particlehttp://en.wikipedia.org/wiki/Heliumhttp://en.wikipedia.org/wiki/Giant_starhttp://en.wikipedia.org/wiki/Supergianthttp://en.wikipedia.org/wiki/Big_Banghttp://en.wikipedia.org/wiki/H-R_diagramhttp://en.wikipedia.org/wiki/Triple-alpha_processhttp://en.wikipedia.org/wiki/Supernovaehttp://en.wikipedia.org/wiki/Solar_Systemhttp://en.wikipedia.org/wiki/Metallicityhttp://en.wikipedia.org/wiki/Metallicityhttp://en.wikipedia.org/wiki/Carbon-nitrogen_cyclehttp://en.wikipedia.org/wiki/Submillimetre_astronomyhttp://en.wikipedia.org/wiki/Star_formationhttp://en.wikipedia.org/wiki/Star_formationhttp://en.wikipedia.org/wiki/Molecular_cloudshttp://en.wikipedia.org/wiki/Carbon_cycle


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2004). The purple numbers indicate how much carbon moves between reservoirs each

year. The sediments, as defined in this diagram, do not include the ~70 million GtC of

carbonate rock and kerogen.

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 thecarbon cycle. For example, plants drawcarbon dioxideout of their

environment and use it to build biomass, as incarbon respiration or the Calvin cycle, a process

ofcarbon 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 orcoal, which can burn with the release of carbon, should

bacteria not consume it.[43]

Compounds

Organic compounds

Main article: Organic compound

Structural formula ofmethane, the simplest possible organic compound.
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Correlation between the carbon cycle and formation of organic compounds. In plants,

carbon dioxide formed by carbon fixation can join with water in photosynthesis (green) to

form organic compounds, which can be used and further converted by both plants and

animals.

Carbon has the ability to form very long chains of interconnecting C-C bonds. This property is

called catenation. Carbon-carbon bonds are strong, and stable. 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 hydrocarbona large family oforganic

molecules that are composed ofhydrogenatoms bonded to a chain of carbon atoms. Chain

length, side chains and functional groupsall affect the properties of organic molecules.

ByIUPAC's definition, all the other organic compounds are functionalized compounds of

hydrocarbons.[citation needed]

Carbon occurs in all known organic life and is the basis oforganic chemistry. When united

withhydrogen, it forms various hydrocarbonswhich are important to industry

asrefrigerants,lubricants,solvents, as chemical feedstock for the manufacture

ofplasticsand petrochemicalsand as fossil fuels.
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When combined with oxygen and hydrogen, carbon can form many groups of important

biological compounds including sugars,lignans, chitins, alcohols,fats, and

aromatic esters,carotenoids and terpenes. With nitrogenit forms alkaloids, and with the

addition of sulfur also it forms antibiotics,amino acids, and rubberproducts. With the addition

of phosphorus to these other elements, it forms DNA and RNA, the chemical-code carriers of

life, and adenosine triphosphate (ATP), the most important energy-transfer molecule in all

living cells.

Inorganic compounds

Main article: Compounds of carbon

Commonly carbon-containing compounds which are associated with minerals or which do not

contain hydrogen or fluorine, are treated separately from classical organic compounds;

however the definition is not rigid (see reference articles above). Among these are the simple

oxides of carbon. The most prominent oxide is carbon dioxide(CO2). This was once theprincipal constituent of the paleoatmosphere, but is a minor component of theEarth's

atmosphere today.[44]Dissolved in water, it formscarbonic acid (H2CO3), but as most

compounds with multiple single-bonded oxygens on a single carbon it is unstable.[45]Through

this intermediate, though, resonance-stabilizedcarbonateions are produced. Some important

minerals are carbonates, notably calcite.Carbon disulfide (CS2) is similar.

The other common oxide iscarbon monoxide (CO). It is formed by incomplete combustion,

and is a colorless, odorless gas. The molecules each contain a triple bond and are fairly polar,

resulting in a tendency to bind permanently to hemoglobin molecules, displacing oxygen,which has a lower binding affinity.[46][47]Cyanide (CN), has a similar structure, but behaves

much like ahalide ion (pseudohalogen). For example it can form the

nitride cyanogenmolecule ((CN)2), similar to diatomic halides. Other uncommon oxides

are carbon suboxide (C3O2),[48] the unstable dicarbon monoxide (C2O),[49][50]carbon

trioxide(CO3),[51][52]cyclopentanepentone (C5O5),[53] cyclohexanehexone (C6O6) ,[53] and mellitic

anhydride (C12O9).

With reactivemetals, such as tungsten, carbon forms eithercarbides(C4),

oracetylides (C22) to form alloys with high melting points. These anions are also associated

withmethaneand acetylene, both very weakacids. With an electronegativity of 2.5,[54]carbon

prefers to form covalent bonds. A few carbides are covalent lattices, like carborundum (SiC),

which resembles diamond.Organometallic compounds

Main article: Organometallic chemistry
http://en.wikipedia.org/wiki/Sugarhttp://en.wikipedia.org/wiki/Sugarhttp://en.wikipedia.org/wiki/Lignanhttp://en.wikipedia.org/wiki/Chitinhttp://en.wikipedia.org/wiki/Alcoholhttp://en.wikipedia.org/wiki/Fathttp://en.wikipedia.org/wiki/Fathttp://en.wikipedia.org/wiki/Esterhttp://en.wikipedia.org/wiki/Esterhttp://en.wikipedia.org/wiki/Carotenoidshttp://en.wikipedia.org/wiki/Terpeneshttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Alkaloidhttp://en.wikipedia.org/wiki/Antibiotichttp://en.wikipedia.org/wiki/Antibiotichttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Rubberhttp://en.wikipedia.org/wiki/Rubberhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/RNAhttp://en.wikipedia.org/wiki/RNAhttp://en.wikipedia.org/wiki/Adenosine_triphosphatehttp://en.wikipedia.org/wiki/Compounds_of_carbonhttp://en.wikipedia.org/wiki/Organic_compoundshttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Paleoatmospherehttp://en.wikipedia.org/wiki/Paleoatmospherehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Carbon#cite_note-43http://en.wikipedia.org/wiki/Carbon#cite_note-43http://en.wikipedia.org/wiki/Water_(molecule)http://en.wikipedia.org/wiki/Water_(molecule)http://en.wikipedia.org/wiki/Carbonic_acidhttp://en.wikipedia.org/wiki/Carbon#cite_note-44http://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Carbon_disulfidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Polar_moleculehttp://en.wikipedia.org/wiki/Carbon#cite_note-45http://en.wikipedia.org/wiki/Carbon#cite_note-46http://en.wikipedia.org/wiki/Carbon#cite_note-46http://en.wikipedia.org/wiki/Cyanidehttp://en.wikipedia.org/wiki/Halidehttp://en.wikipedia.org/wiki/Halidehttp://en.wikipedia.org/wiki/Pseudohalogenhttp://en.wikipedia.org/wiki/Cyanogenhttp://en.wikipedia.org/wiki/Cyanogenhttp://en.wikipedia.org/wiki/Carbon_suboxidehttp://en.wikipedia.org/wiki/Carbon#cite_note-47http://en.wikipedia.org/wiki/Carbon#cite_note-47http://en.wikipedia.org/wiki/Dicarbon_monoxidehttp://en.wikipedia.org/wiki/Carbon#cite_note-48http://en.wikipedia.org/wiki/Carbon#cite_note-49http://en.wikipedia.org/wiki/Carbon#cite_note-49http://en.wikipedia.org/wiki/Carbon_trioxidehttp://en.wikipedia.org/wiki/Carbon_trioxidehttp://en.wikipedia.org/wiki/Carbon_trioxidehttp://en.wikipedia.org/wiki/Carbon#cite_note-50http://en.wikipedia.org/wiki/Carbon#cite_note-51http://en.wikipedia.org/wiki/Cyclopentanepentonehttp://en.wikipedia.org/wiki/Carbon#cite_note-fatiadi-52http://en.wikipedia.org/wiki/Carbon#cite_note-fatiadi-52http://en.wikipedia.org/wiki/Cyclohexanehexonehttp://en.wikipedia.org/wiki/Carbon#cite_note-fatiadi-52http://en.wikipedia.org/wiki/Mellitic_anhydridehttp://en.wikipedia.org/wiki/Mellitic_anhydridehttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Tungstenhttp://en.wikipedia.org/wiki/Tungstenhttp://en.wikipedia.org/wiki/Carbidehttp://en.wikipedia.org/wiki/Carbidehttp://en.wikipedia.org/wiki/Acetylidehttp://en.wikipedia.org/wiki/Methanehttp://en.wikipedia.org/wiki/Methanehttp://en.wikipedia.org/wiki/Acetylenehttp://en.wikipedia.org/wiki/Acidhttp://en.wikipedia.org/wiki/Acidhttp://en.wikipedia.org/wiki/Carbon#cite_note-53http://en.wikipedia.org/wiki/Carbon#cite_note-53http://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Silicon_carbidehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Organometallic_chemistryhttp://en.wikipedia.org/wiki/Sugarhttp://en.wikipedia.org/wiki/Lignanhttp://en.wikipedia.org/wiki/Chitinhttp://en.wikipedia.org/wiki/Alcoholhttp://en.wikipedia.org/wiki/Fathttp://en.wikipedia.org/wiki/Esterhttp://en.wikipedia.org/wiki/Carotenoidshttp://en.wikipedia.org/wiki/Terpeneshttp://en.wikipedia.org/wiki/Nitrogenhttp://en.wikipedia.org/wiki/Alkaloidhttp://en.wikipedia.org/wiki/Antibiotichttp://en.wikipedia.org/wiki/Amino_acidhttp://en.wikipedia.org/wiki/Rubberhttp://en.wikipedia.org/wiki/DNAhttp://en.wikipedia.org/wiki/RNAhttp://en.wikipedia.org/wiki/Adenosine_triphosphatehttp://en.wikipedia.org/wiki/Compounds_of_carbonhttp://en.wikipedia.org/wiki/Organic_compoundshttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Paleoatmospherehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Earth's_atmospherehttp://en.wikipedia.org/wiki/Carbon#cite_note-43http://en.wikipedia.org/wiki/Water_(molecule)http://en.wikipedia.org/wiki/Carbonic_acidhttp://en.wikipedia.org/wiki/Carbon#cite_note-44http://en.wikipedia.org/wiki/Carbonatehttp://en.wikipedia.org/wiki/Ionhttp://en.wikipedia.org/wiki/Calcitehttp://en.wikipedia.org/wiki/Carbon_disulfidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Polar_moleculehttp://en.wikipedia.org/wiki/Carbon#cite_note-45http://en.wikipedia.org/wiki/Carbon#cite_note-46http://en.wikipedia.org/wiki/Cyanidehttp://en.wikipedia.org/wiki/Halidehttp://en.wikipedia.org/wiki/Pseudohalogenhttp://en.wikipedia.org/wiki/Cyanogenhttp://en.wikipedia.org/wiki/Carbon_suboxidehttp://en.wikipedia.org/wiki/Carbon#cite_note-47http://en.wikipedia.org/wiki/Dicarbon_monoxidehttp://en.wikipedia.org/wiki/Carbon#cite_note-48http://en.wikipedia.org/wiki/Carbon#cite_note-49http://en.wikipedia.org/wiki/Carbon_trioxidehttp://en.wikipedia.org/wiki/Carbon_trioxidehttp://en.wikipedia.org/wiki/Carbon#cite_note-50http://en.wikipedia.org/wiki/Carbon#cite_note-51http://en.wikipedia.org/wiki/Cyclopentanepentonehttp://en.wikipedia.org/wiki/Carbon#cite_note-fatiadi-52http://en.wikipedia.org/wiki/Cyclohexanehexonehttp://en.wikipedia.org/wiki/Carbon#cite_note-fatiadi-52http://en.wikipedia.org/wiki/Mellitic_anhydridehttp://en.wikipedia.org/wiki/Mellitic_anhydridehttp://en.wikipedia.org/wiki/Metalhttp://en.wikipedia.org/wiki/Tungstenhttp://en.wikipedia.org/wiki/Carbidehttp://en.wikipedia.org/wiki/Acetylidehttp://en.wikipedia.org/wiki/Methanehttp://en.wikipedia.org/wiki/Acetylenehttp://en.wikipedia.org/wiki/Acidhttp://en.wikipedia.org/wiki/Carbon#cite_note-53http://en.wikipedia.org/wiki/Covalent_bondhttp://en.wikipedia.org/wiki/Silicon_carbidehttp://en.wikipedia.org/wiki/Diamondhttp://en.wikipedia.org/wiki/Organometallic_chemistry


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Organometallic compounds by definition contain at least one carbon-metal bond. A wide range

of such compounds exist; major classes include simple alkyl-metal compounds

(e.g.tetraethyllead), 2-alkene compounds (e.g.Zeise's salt, and 3-allyl compounds

(e.g. allylpalladium chloride dimer;metallocenes containing cyclopentadienyl ligands

(e.g. ferrocene); andtransition metal carbene complexes. Many metal carbonyls exist

(e.g. tetracarbonylnickel); some workers consider the carbon monoxide ligand to be purely

inorganic, and not organometallic.

While carbon is understood to exclusively form four bonds, an interesting compound containing

an octahedral hexacoordinated carbon atom has been reported. The cation of the compound is

[(Ph3PAu)6C]2+. This phenomenon has been attributed to the aurophilicity of the gold ligands.[55]

History and etymology

Antoine Lavoisierin his youth

The English name carbon comes from theLatincarbo for coal and charcoal,[56] and from hence

also comes the Frenchcharbon, meaning charcoal. InGerman, DutchandDanish, the names

for carbon are Kohlenstoff, koolstofand kulstofrespectively, all literally meaning coal-

substance.

Carbon was discovered in prehistory and was known in the forms ofsootandcharcoalto the

earliest humancivilizations. Diamonds were known probably as early as 2500 BCE in China,

while carbon in the form ofcharcoal was made around Roman times by the same chemistry as

it is today, by heating wood in a pyramid covered withclayto exclude air.

[57][58]
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Carl Wilhelm Scheele

In 1722, Ren Antoine Ferchault de Raumurdemonstrated that iron was transformed into

steel through the absorption of some substance, now known to be carbon.[59] In 1772, Antoine

Lavoisiershowed that diamonds are a form of carbon, when he burned samples of carbon and

diamond then showed that neither produced any water and that both released the same

amount ofcarbon dioxidepergram.Carl Wilhelm Scheeleshowed that graphite, which had

been thought of as a form oflead, was instead a type of carbon.[60] In 1786, the French

scientists Claude Louis Berthollet,Gaspard Monge and C. A. Vandermonde then showed that

this substance was carbon.[61]In their publication they proposed the name carbone (Latin

carbonum) for this element. Antoine Lavoisier listed carbon as anelementin his 1789 textbook.

[62]

A newallotrope of carbon, fullerene, that was discovered in

1985[63] includes nanostructured forms such as buckyballsand nanotubes.[19] Their discoverers

(Curl, Kroto, and Smalley) received the Nobel Prize in Chemistry in 1996.[64] The resulting

renewed interest in new forms lead to the discovery of further exotic allotropes,

including glassy carbon, and the realization that "amorphous carbon" is not strictlyamorphous.

[26]

Production

Graphite

Main article: Graphite

Commercially viable natural deposits of graphite occur in many parts of the world, but the most

important sources economically are inChina,India, Brazil, and North Korea.[65] Graphite

deposits are ofmetamorphicorigin, found in association with quartz,micaandfeldspars in

schists, gneisses and metamorphosed sandstones andlimestoneas lensesorveins,

sometimes of a meter or more in thickness. Deposits of graphite
http://en.wikipedia.org/wiki/Carl_Wilhelm_Scheelehttp://en.wikipedia.org/wiki/Ren%C3%A9_Antoine_Ferchault_de_R%C3%A9aumurhttp://en.wikipedia.org/wiki/Carbon#cite_note-58http://en.wikipedia.org/wiki/Antoine_Lavoisierhttp://en.wikipedia.org/wiki/Antoine_Lavoisierhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Gramhttp://en.wikipedia.org/wiki/Gramhttp://en.wikipedia.org/wiki/Gramhttp://en.wikipedia.org/wiki/Carl_Wilhelm_Scheelehttp://en.wikipedia.org/wiki/Carl_Wilhelm_Scheelehttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Carbon#cite_note-59http://en.wikipedia.org/wiki/Claude_Louis_Berthollethttp://en.wikipedia.org/wiki/Claude_Louis_Berthollethttp://en.wikipedia.org/wiki/Gaspard_Mongehttp://en.wikipedia.org/wiki/Carbon#cite_note-60http://en.wikipedia.org/wiki/Carbon#cite_note-60http://en.wikipedia.org/wiki/Carbon#cite_note-60http://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Carbon#cite_note-61http://en.wikipedia.org/wiki/Allotropehttp://en.wikipedia.org/wiki/Allotropehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Carbon#cite_note-62http://en.wikipedia.org/wiki/Nanostructurehttp://en.wikipedia.org/wiki/Buckyballshttp://en.wikipedia.org/wiki/Buckyballshttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Nobel_Prizehttp://en.wikipedia.org/wiki/Carbon#cite_note-63http://en.wikipedia.org/wiki/Carbon#cite_note-63http://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Carbon#cite_note-glassy_carbon-25http://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Brazilhttp://en.wikipedia.org/wiki/North_Koreahttp://en.wikipedia.org/wiki/Carbon#cite_note-64http://en.wikipedia.org/wiki/Carbon#cite_note-64http://en.wikipedia.org/wiki/Metamorphic_rockhttp://en.wikipedia.org/wiki/Metamorphic_rockhttp://en.wikipedia.org/wiki/Metamorphic_rockhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Gneisshttp://en.wikipedia.org/wiki/Sandstonehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Lens_(geology)http://en.wikipedia.org/wiki/Lens_(geology)http://en.wikipedia.org/wiki/Vein_(geology)http://en.wikipedia.org/wiki/File:Carl_Wilhelm_Scheele_from_Familj-Journalen1874.pnghttp://en.wikipedia.org/wiki/File:Carl_Wilhelm_Scheele_from_Familj-Journalen1874.pnghttp://en.wikipedia.org/wiki/Carl_Wilhelm_Scheelehttp://en.wikipedia.org/wiki/Ren%C3%A9_Antoine_Ferchault_de_R%C3%A9aumurhttp://en.wikipedia.org/wiki/Carbon#cite_note-58http://en.wikipedia.org/wiki/Antoine_Lavoisierhttp://en.wikipedia.org/wiki/Antoine_Lavoisierhttp://en.wikipedia.org/wiki/Carbon_dioxidehttp://en.wikipedia.org/wiki/Gramhttp://en.wikipedia.org/wiki/Carl_Wilhelm_Scheelehttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Carbon#cite_note-59http://en.wikipedia.org/wiki/Claude_Louis_Berthollethttp://en.wikipedia.org/wiki/Gaspard_Mongehttp://en.wikipedia.org/wiki/Carbon#cite_note-60http://en.wikipedia.org/wiki/Chemical_elementhttp://en.wikipedia.org/wiki/Carbon#cite_note-61http://en.wikipedia.org/wiki/Allotropehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/Carbon#cite_note-62http://en.wikipedia.org/wiki/Nanostructurehttp://en.wikipedia.org/wiki/Buckyballshttp://en.wikipedia.org/wiki/Carbon_nanotubehttp://en.wikipedia.org/wiki/Carbon#cite_note-buckyballs-18http://en.wikipedia.org/wiki/Nobel_Prizehttp://en.wikipedia.org/wiki/Carbon#cite_note-63http://en.wikipedia.org/wiki/Glassy_carbonhttp://en.wikipedia.org/wiki/Amorphous_carbonhttp://en.wikipedia.org/wiki/Amorphoushttp://en.wikipedia.org/wiki/Carbon#cite_note-glassy_carbon-25http://en.wikipedia.org/wiki/Graphitehttp://en.wikipedia.org/wiki/Chinahttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Brazilhttp://en.wikipedia.org/wiki/North_Koreahttp://en.wikipedia.org/wiki/Carbon#cite_note-64http://en.wikipedia.org/wiki/Metamorphic_rockhttp://en.wikipedia.org/wiki/Quartzhttp://en.wikipedia.org/wiki/Micahttp://en.wikipedia.org/wiki/Feldsparhttp://en.wikipedia.org/wiki/Gneisshttp://en.wikipedia.org/wiki/Sandstonehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Lens_(geology)http://en.wikipedia.org/wiki/Vein_(geology)


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inBorrowdale,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.

According to the USGS, world production of natural graphite in 2006 was 1.03 million tons and

in 2005 was 1.04 million tons (revised), of which the following major exporters produced: China

produced 720,000 tons in both 2006 and 2005, Brazil 75,600 tons in 2006 and 75,515 tons in

2005 (revised), Canada 28,000 tons in both years, and Mexico (amorphous) 12,500 tons in

2006 and 12,357 tons in 2005 (revised). In addition, there are two specialist producers: Sri

Lanka produced 3,200 tons in 2006 and 3,000 tons in 2005 of lump or vein graphite, and

Madagascar produced 15,000 tons in both years, a large portion of it "crucible grade" or very

large flake graphite. Some other producers produce very small amounts of "crucible grade".

According to the USGS, U.S. (synthetic) graphite electrode production in 2006 was

132,000 tons valued at $495 million and in 2005 was 146,000 tons valued at $391 million, and

high-modulus graphite (carbon) fiber production in 2006 was 8,160 tons valued at $172 million

and in 2005 was 7,020 tons valued at $134 million.

Diamond

Main article: Diamond

Diamond output in 2005

The diamond supply chain is controlled by a limited number of powerful businesses, and is

also highly concentrated in a small number of locations around the world (see figure).

Only a very small fraction of the diamond ore consists of actual diamonds. The ore is crushed,

during which care has to be taken in order to prevent larger diamonds from being destroyed in

this process and subsequently the particles are sorted by density. Today, diamonds are

located in the diamond-rich density fraction with the help ofX-ray fluorescence, after which the

final sorting steps are done by hand. Before the use ofX-rays became commonplace, the

separation was done with grease belts; diamonds have a stronger tendency to stick to grease

than the other minerals in the ore.[66]
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Documents

Carbon - An Introduction