Carbon – the chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity.
Theoretical phase diagram of carbon, which shows the state of matter for varying temperatures and pressures.
Forms of Carbon (allotropes)
- diamond – among the hardest materials known
- carbon nanotube
Diamond has a very low electrical conductivity, while graphite is a very good conductor. Under normal conditions, diamond, carbon nanotube and graphene have the highest thermal conductivities of all known materials.