What is the chemical element with atomic number 6?

The chemical element with atomic number 6 is carbon. Its chemical symbol is C, and every carbon atom has six protons in its nucleus—the defining feature of the element.

Carbon is a nonmetal in group 14 of the periodic table. It is unusually versatile because each atom can form up to four covalent bonds, allowing carbon atoms to build chains, rings, sheets, and three-dimensional networks. This bonding flexibility is the foundation of organic chemistry and makes carbon central to all known life.

The same element can appear in very different forms called allotropes. Graphite consists of layered sheets and conducts electricity, while diamond forms a rigid three-dimensional crystal and is extremely hard. Other carbon structures include fullerenes, graphene, and carbon nanotubes.

Carbon also has important isotopes. Carbon-12 and carbon-13 are stable, while radioactive carbon-14 has a half-life of about 5,700 years and is used in radiocarbon dating. Carbon is also found throughout stars, planets, oceans, rocks, fuels, and living organisms.