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Carbon-14, C-14, 14 C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples.
Two are stable and not radioactive: carbon-12 (12 C), and carbon-13 (13 C); and carbon-14 (14 C), also known as "radiocarbon", which is radioactive. The half-life of 14 C (the time it takes for half of a given amount of 14 C to decay) is about 5,730 years, so its concentration in the atmosphere might be expected to decrease over thousands of ...
For instance, carbon-14 has a half-life of 5,730 years. After an organism has been dead for 60,000 years, so little carbon-14 is left that accurate dating cannot be established. On the other hand, the concentration of carbon-14 falls off so steeply that the age of relatively young remains can be determined precisely to within a few decades. [13]
Its maximum specific activity is 0.0624 kCi/mol (2.31 TBq/mol). It is used in applications such as radiometric dating or drug tests. [6] Carbon-14 labeling is common in drug development to do ADME (absorption, distribution, metabolism and excretion) studies in animal models and in human toxicology and clinical trials. Since tritium exchange may ...
14 C is constantly formed from nitrogen-14 (14 N) in the upper atmosphere by cosmic rays which generate neutrons. These neutrons hit 14 N to produce 14 C which then combines with oxygen to form 14 CO 2. This radioactive CO 2 spreads through the lower atmosphere and the oceans where it is absorbed by plants, and animals that eat the plants.
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Carbon (6 C) has 14 known isotopes, from 8 C to 20 C as well as 22 C, of which 12 C and 13 C are stable.The longest-lived radioisotope is 14 C, with a half-life of 5.70(3) × 10 3 years. . This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reactio
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