Carbon

Carbon () is a chemical element; it has symbol C and atomic number 6. It is nonmetallic and tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 electrons. It belongs to group 14 of the periodic table. Carbon makes up about 0.025 percent of Earth's crust. Three isotopes occur naturally, C and C being stable, while C is a radionuclide, decaying with a half-life of 5,700 years. Carbon is one of the few elements known since antiquity.

technique based on carbon-14 decay to determine the age of organic materials

set of fusion reactions by which stars convert hydrogen to helium: 4¹H+2e⁻→⁴He+2e⁺+2e⁻+2νₑ+3γ+24.7 MeV→⁴He+2νₑ+3γ+26.7 MeV

climate change-induced decline of pH levels in the ocean

nuclear fusion reaction chain converting helium to carbon

chemical substance

extrasolar terrestrial planet

conversion of carbon from CO2 to organic compounds

metabolic pathway for carbon fixation in photosynthesis

medication used to treat ingested poisonings

allotrope of carbon

assumption that the chemical processes of hypothetical extraterrestrial life must be constructed primarily from carbon

concentration of organic carbon in a sample

production facility where coke and raw gas is produced

analytical method

In geochemistry, paleoclimatology, archaeology, and paleoceanography '''δC''' (pronounced "delta carbon thirteen") is a normalized ratio of the two stable isotopes of carbon—C and C—reported in parts per thousand (per mille, ‰).

Methylotrophs are a diverse group of microorganisms that can use reduced one-carbon compounds, such as methanol or methane, as the carbon source for their growth; and multi-carbon compounds that contain no carbon-carbon bonds, such as dimethyl ether and dimethylamine. This group of microorganisms also includes those capable of assimilating reduced one-carbon compounds by way of carbon dioxide using the ribulose bisphosphate pathway. These organisms should not be confused with methanogens which on the contrary produce methane as a by-product from various one-carbon compounds such as carbon diox

life whose primary component is carbon

Emission spectra characteristic of burning hydrocarbon fuels

chemical compound

global research program designed to transform understanding of carbon's role in Earth

threat to the reef which reduces the viability and strength of reef-building corals

measure of greenhouse gas emissions

solid carbon stored in global soils