Carbon is the element with the largest number of chemical compounds, with more than 10 million known to date. Carbon is the fourth most common element in the universe. Each carbon atom can bond to four other carbon atoms, allowing them to form chains and rings. Pure carbon exists in three forms (allotropes) on Earth: graphite, diamond and buckminsterfullerene (spherical structure with 60 carbon atoms bonded together to form 12 pentagons and 20 hexagons).

Diamond is the hardest substance in nature, and used in jewelry. Also, the blades of some saws are coated with diamonds and can cut any material except another diamond. Graphite is much softer, which is why it is used in pencils, and is also used in some batteries. Coal is currently the largest source of fuel for electricity generation. Crude oil, natural gas and coal are naturally occurring hydrocarbons.

Summary of properties (C)

Atomic weight[12.0096, 12.0106]
Discoverer (year)desconocido (~ 1694)
Natural formnon-metal solid (hexagonal)
Electron configuration[He] 2s2 2p2
Melting point (ºC)3500
Boiling point (ºC)4827
Abundance in earth's crust (ppm)200
Isotope (abundance)12C (98.93), 13C (1.07)
Density g/cm32.26
Van der Waals radius (pm)170
Covalent radius (pm)75
Electronegativity (Pauling)2.55
Vaporization enthalpy (kJ/mol)771.00
Enthalpy of fusion (kJ/mol)117.00
Specific heat capacity (J/g·K) at 25ºC and 1 atm0.71
Thermal conductivity (W/cm·K) at 25ºC and 1 atm1.960
Oxidation state+4, +2, -4
Electron affinity (eV)1.26
1st Ionization potential (eV)11.2603

Back to the Periodic Table of the Elements.