Isotopes of carbon

Carbon with different numbers of neutrons

Carbon (6C) has 14 known isotopes, from 8C to 20C as well as 22C, of which 12C and 13C are stable. The longest-lived radioisotope is 14C, with a half-life of 5.70(3)×103 years. This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reaction 14N + n → 14C + 1H. The most stable artificial radioisotope is 11C, which has a half-life of 20.3402(53) min. All other radioisotopes have half-lives under 20 seconds, most less than 200 milliseconds. The least stable isotope is 8C, with a half-life of 3.5(1.4)×10−21 s. Light isotopes tend to decay into isotopes of boron and heavy ones tend to decay into isotopes of nitrogen.

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