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Carbon
Occurs naturally as graphite and
diamond; known to prehistoric humans.
[Latin: carbo = charcoal]
French: carbone
German: Kohlenstoff
Italian: carbonio
Spanish: carbono
Description: Carbon
occurs in three forms: graphite, diamond and buckminsterfullerene
C60. It is mainly used in its amorphous forms: as coke in steel
melting, as carbon black in printing, and as a filler, and as activated charcoal
in sugar refining, water treatment and in respirators.
Materials properties
| Density: |
3513 (diam.); 2260 (graph); 1650 (C60) kg/m-3 |
| Melting point: |
3820 (diam.); 3800 (graph.) 800 (C60 sublimes) °K |
| Boiling point: |
5100 (sublimes) °K |
| Molar volume: |
3.42 (diam.) cm3 |
| Thermal conductivity: |
990 - 2320 (diam.); 5.7; 1960 (graph) Wm-1K-1 |
| Coefficient of linear thermal expansion: |
1.19 x 10-6 K-1 |
| Electrical resistivity: |
1 x 1011 (diam.); 1.375 x 10-5 (graph); 1 x 1014 (C 60)[293K]Wm |
| Mass magnetic susceptibility: |
-6.3 x 10-9(graph.); -6.2 x 10-9(diam.) kg-1m3 |
| Radii: |
4 - 260; atomic 77covalentC-C 77; C=C 67; van der Waals 185 |
| Electronegativity: |
2.55 (Pauling); 2.50 (Allred); 6.27 eV (absolute) |
| Effective nuclear charge: |
3.25 (Slater); 3.14 (Clementi); 2.87 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): |
8 |
| Issotope mass range: |
9 -> 16 |
Biological data
| Biological role: |
Constituent element of DNA |
| Toxicity |
Non-toxic as the element, but some simple compounds can be very toxic, such as CO or cyanide CN-. |
| Lethal intake: |
n.a. |
| Hazards: |
Carbon black can be a nuisance dust but is not itself dangerous, although soot may harbour carcinogenic materials. |
| Level in humans |
|
| Blood: |
0.0016 - 0.075 mg dm-3 |
| Bone: |
300 000 p.p.m. |
| Liver: |
670 000 p.p.m. |
| Muscle: |
670 000 p.p.m. |
| Daily dietary intake : |
300 g |
| Total mass of element in average [70 kg] person: |
16 kg |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
Cubic diamond (a=356.703), Fd3m
Hexagonal diamond (a=252, c=412), P63/mmc
Hexagonal graphite (a=246.12, c=670.78), P63mc
Rhombohedral graphite (a=364.2, α=39° 30' ), R3m
Hexagonal carbon [chaoite] (a=894.8, c=1408)
F.c.c. buckminsterfullerene C60 (a=1414) |
| X-ray diffraction: mass absorption coefficients (µ/ρ)/cm2g-1: |
CuKα 4.60 MoKα 0.625 |
| Neutron scattering length, b/10-12cm: |
0.66460 |
| Thermal neutron capture cross-section, σa/barns: |
0.0035 |
Geological data
| Minerals: |
Carbon is commonly found in as graphite, very rarely as diamond, and only in minute traces as C60 . Carbon is also found as fossil fuel deposits and as carbonates, in particular calcium/magnesium carbonates. |
| Mineral |
Formula |
Density |
Hardness |
Crystal apperance |
| Diamond |
C |
3.51 |
10 |
cub., crystalline, col./pale tints |
| Graphite |
C |
2.2 |
1 - 2 |
hex., met. black sheets, sometimes crystals |
| Chief ore: |
graphite |
| World production: |
8.6 x 109 tonnes/year (fossil carbon,1996). Fossil fuel production: natural gas, 2.0 x 109; oil, 3.3 x 109; coal, 2.3 x 109 |
| Main mining areas: |
graphite deposits: Sri Lanka, Madagascar, Russia, South Korea, Mexico, Czech Republic, Italy. Diamonds: South Africa, USA, Russia, Brazil, Zaire, Sierra Leone, Ghana. |
| Reserves: |
naural gas, 127 x 109 ; oil, 140 x 109 ; coal, 1000 x 109 tonnes; tar sands, n.a. but large |
| Specimen: |
available as amorphous, fullerenes, bucky tubes, diamond, graphite and soot. Safe. |
| Abundances |
|
| Sun: |
4.17 x 108 (relative to H = 1 x 1023) |
| Earth's crust: |
480 p.p.m. |
| Atmosphere: |
c. 350 (CO2) p.p.m.(volume) |
| Atlantic surface: |
23 p.p.m. |
| Atlantic deep: |
26 p.p.m. |
| Pacific surface: |
23 p.p.m. |
| Pacific deep: |
28 p.p.m. |
| Residence time: |
800 000 years |
| Classification: |
recycled |
| Oxidation state: |
IV |
Other sizes and specifications on request
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