Carbon

boron ← carbon → nitrogen - ↑ C ↓ Si 6C Periodic table
Appearance
clear (diamond) & black (graphite) Spectral lines of Carbon
General properties
Name, symbol, number	carbon, C, 6
Pronunciation	/ˈkɑrbən/
Element category	nonmetal
Group, period, block	14, 2, p
Standard atomic weight	12.011(1) g·mol−1
Electron configuration	[He] 2s2 2p2
Electrons per shell	2, 4 (Image)
Physical properties
Phase	solid
Density (near r.t.)	amorphous: 1.8–2.1 g·cm−3
Density (near r.t.)	diamond: 3.515 g·cm−3
Density (near r.t.)	graphite: 2.267 g·cm−3
Sublimation point	3915 K, 3642 °C, 6588 °F
Triple point	4600 K (4327°C), 10800 kPa
Heat of fusion	117 (graphite) kJ·mol−1
Specific heat capacity	(25 °C) 6.155 (diamond) 8.517 (graphite) J·mol−1·K−1
Atomic properties
Oxidation states	4, 3, 2, 1, 0, −1, −2, −3, −4
Electronegativity	2.55 (Pauling scale)
Ionization energies	1st: 1086.5 kJ·mol−1
	2nd: 2352.6 kJ·mol−1
	3rd: 4620.5 kJ·mol−1
Covalent radius	77(sp³), 73(sp²), 69(sp) pm
Van der Waals radius	170 pm
Miscellanea
Crystal structure	diamond
Crystal structure note	(diamond, clear)
Magnetic ordering	diamagnetic
Thermal conductivity	(300 K) 900-2300 (diamond) 119-165 (graphite) W·m−1·K−1
Thermal expansion	(25 °C) 0.8 (diamond) µm·m−1·K−1
Speed of sound (thin rod)	(20 °C) 18350 (diamond) m/s
Young's modulus	1050 (diamond) GPa
Shear modulus	478 (diamond) GPa
Bulk modulus	442 (diamond) GPa
Poisson ratio	0.1 (diamond)
Mohs hardness	10 (diamond) 1-2 (graphite)
CAS registry number	7440-44-0
Most stable isotopes
Main article: Isotopes of carbon
iso NA half-life DM DE (MeV) DP 15 11C syn 20 min β+ 0.96 11B 12C 98.9% 12C is stable with 6 neutrons 13C 1.1% 13C is stable with 7 neutrons 14C trace 5730 y β− 0.15 14N

Carbon is a very important chemical element, with a chemical symbol of C. All known life on Earth is made from it. Carbon has atomic mass 12 and atomic number 6. It is non-metallic, meaning that it is not a metal.

Why it is important

Carbon, hydrogen, nitrogen, oxygen, and some other elements like sulfur and phosphorus together form most life on earth (see Organic chemistry and List of biologically important elements). Carbon forms a very large number of organic compounds because it can form strong bonds with itself and with other elements. Because of the amounts of carbon living things have, all organic things are considered "carbon-based". Also, each carbon atom can form 4 single covalent bonds. Many carbon atoms linked together with hydrogen atoms form plastic. Also, Carbon is the only element that can form long chain-shaped molecules. When iron is heated up with carbon, hard steel is formed.

Etymology

The name of carbon comes from Latin carbo, meaning charcoal. In many foreign languages the words for carbon, coal and charcoal are synonyms.

Types of carbon

Main page: Allotropes of carbon

Carbon in nature is found in three forms called allotropes: diamond, graphite, and fullerenes. Graphite, with clay, is in pencils. It is very soft. The carbon atoms in it make rings, which are on top of each other and slide very easily. Diamonds are the hardest natural mineral. Fullerenes are a "soccer ball" shape of carbon. They are mostly of interest to science. A special, man-made, tube-shaped allotrope of carbon is the carbon nanotube. Carbon nanotubes are very hard, so they might be used in armor. Nanotubes might be useful in nanotechnology. There are 10 million known carbon compounds.

Some allotropes of carbon: a) diamond; b) graphite; c) lonsdaleite; d-f) fullerenes (C60, C540, C70); g) amorphous carbon; h) carbon nanotube.

Chemistry of Carbon

A whole type of Chemistry, organic chemistry, is about carbon and its compounds. Carbon makes many types of compounds. Hydrocarbons are molecules with carbon and hydrogen. Methane, Propane, and many other fuels are hydrocarbons. Many of the substances that people use daily are organic compounds.

Radiocarbon dating

Main page: Radiocarbon dating

A radioactive isotope of carbon, carbon-14, can be used to figure out how old some objects are or when something died. As long as something is on the surface of the earth and taking in carbon, the amount of carbon-14 stays the same. When an object stops taking in carbon, the carbon-14 amount goes down. Because the half-life (how long it takes for half of a radioactive isotope to go away) of carbon-14 is 5730 years, scientists can see how old the object is by how much carbon-14 is left.

Where Carbon Is

Carbon in Space

Carbon is in many places in the universe. It was first made in old stars. Carbon is the fourth most common element in the sun. Almost all of the atmosphere of Mars is Carbon dioxide.

Carbon in People

It is important to the human body, and it is the second most common element in the human body, at 23% of all body weight. It is also a key part of many biological molecules (molecules used in life).

Carbon on Earth

Graphite is in many areas, including Sri Lanka, Madagascar, and Russia. Diamonds are rare and are found largely in Africa. Carbon is also in some meteorites.

Other pages

• List of common elements

Other websites

• Carbon at Webelements