is a chemical element in the periodic table that has the
and atomic number 6.
An abundant nonmetallic,
tetravalent element, carbon has several allotropic
- Diamond : Hardest known natural mineral.
Structure: each atom is bonded tetrahedrally to four
others, making a 3-dimensional network of puckered
six-membered rings of atoms.
- Graphite : One of the softest substances.
Structure: each atom is bonded trigonally to three
other atoms, making a 2-dimensional network of flat
six-membered rings; the flat sheets are loosely
- Fullerenes : Structure: comparatively large
molecules formed completely of carbon bonded
trigonally, forming spheroids (of which the
best-known and simplest is the buckminsterfullerene
- Chaoite : A mineral believed to be formed in
- Lonsdaleite : A corruption of diamond.
Structure: similar to diamond, but forming a
hexagonal crystal lattice.
- Amorphous carbon : A glassy substance.
Structure: an assortment of carbon molecules in a
non-crystalline, irregular, glassy state.
- Carbon nanofoam : An extremely light magnetic
web. Structure: a low-density web of graphite-like
clusters, in which the atoms are bonded trigonally
in six- and seven-membered rings.
- Carbon nanotubes : Tiny tubes. Structure: each
atom is bonded trigonally in a curved sheet that
forms a hollow cylinder.
- Aggregated diamond nanorods : The most recently
discovered allotrope and the hardest substance known
- Lamp black : Consists of small graphitic areas.
These areas are randomly distributed, so the whole
structure is isotropic.
- 'Glassy carbon' : An isotropic substance that
contains a high proportion of closed porosity.
Unlike normal graphite, the graphitic layers are not
stacked like pages in a book, but have a more random
Carbon fibers are similar to glassy carbon. Under
special treatment (stretching of organic fibers and
carbonization) it is possible to arrange the carbon
planes in direction of the fiber. Perpendicular to the
fiber axis there is no orientation of the carbon planes.
The result are fibers with a higher specific strength
Carbon occurs in all organic life and is the basis of
organic chemistry. This nonmetal also has the
interesting chemical property of being able to bond with
itself and a wide variety of other elements, forming
nearly 10 million known compounds. When united with
oxygen it forms carbon dioxide which is absolutely vital
to plant growth. When united with hydrogen, it forms
various compounds called hydrocarbons which are
essential to industry in the form of fossil fuels. When
combined with both oxygen and hydrogen it can form many
groups of compounds including fatty acids, which are
essential to life, and esters, which give flavor to many
fruits. The isotope carbon-14 is commonly used in
Carbon is a remarkable element for many reasons. Its
different forms include one of the softest (graphite)
and one of the hardest (diamond) substances known.
Moreover, it has a great affinity for bonding with other
small atoms, including other carbon atoms, and its small
size makes it capable of forming multiple bonds. Because
of these properties, carbon is known to form nearly ten
million different compounds, the large majority of all
chemical compounds. Carbon compounds form the basis of
all life on Earth and the carbon-nitrogen cycle provides
some of the energy produced by the sun and other stars.
Moreover, carbon has the highest melting/sublimation
point of all elements. At atmospheric pressure it has no
actual melting point as its triple point is at 10 MPa
(100 bar) so it sublimates above 4000 K. Thus it remains
solid at higher temperatures than the highest melting
point metals like tungsten or rhenium, regardless of its
Carbon was not created in the Big
Bang due to the fact that it needs a triple collision of
alpha particles (helium nuclei) to be produced. The
universe initially expanded and cooled too fast for that
to be possible. It is produced, however, in the interior
of stars in the horizontal branch, where stars transform
a helium core into carbon by means of the triple-alpha
process. It was also created in a multi atomic state.
steel 316L flange pipe F316L F304L 304 A269 A312
|Name, Symbol, Number
||carbon, C, 6
|Group, Period, Block
||14, 2, p
||1s2 2s2 2p2
|Electrons per shell
|Density (near r.t.)
||(graphite) 2.267 g/cm³
|Density (near r.t.)
||(diamond) 3.513 g/cm³
||triple point, ca. 10 MPa
and (4300¡V4700) K
||subl. ca. 4000 K
(3727 ¢XC, 6740 ¢XF)
|Heat of fusion
||(graphite) 100 kJ/mol
|Heat of fusion
||(diamond) 120 kJ/mol
|Heat of vaporization
||(25 ¢XC) (graphite)
||(25 ¢XC) (diamond)
Vapor pressure (graphite)
(mildly acidic oxide)
||2.55 (Pauling scale)
|1st: 1086.5 kJ/mol
|2nd: 2352.6 kJ/mol
|3rd: 4620.5 kJ/mol
|Atomic radius (calc.)
|Van der Waals radius
||(300 K) (graphite)
||(300 K) (diamond)
||(300 K) (diamond)
|CAS registry number
Main article: Isotopes of carbon
||C is stable with 6 neutrons
||C is stable with 7 neutrons
Carbon is a vital component of
all known living systems, and without it life as we know it could not
exist (see alternative biochemistry). The major economic use of carbon
is in the form of hydrocarbons, most notably the fossil fuels methane
gas and crude oil (petroleum). Crude oil is used by the petrochemical
industry to produce, amongst others, gasoline and kerosene, through a
distillation process, in refineries. Crude oil forms the raw material
for many synthetic substances, many of which are collectively called
- The isotope carbon-14 was discovered in February
27, 1940 and is used in radiocarbon dating.
- Graphite is combined with clays to form the
'lead' used in pencils.
- Diamond is used for decorative purposes, and
also as drill bits and other applications making use
of its hardness.
- Carbon is added to iron to make steel.
- Carbon is used as a neutron moderator in nuclear
- Graphite carbon in a powdered, caked form is
used as charcoal for cooking, artwork and other
- Activated charcoal is used in medicine (as
powder or compounded in tablets or capsules) to
absorb toxins or poisons from the digestive system.
The chemical and structural properties of fullerenes,
in the form of carbon nanotubes, has promising potential
uses in the nascent field of nanotechnology.
Nanoparticles might however be toxic.
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