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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 reaction 14 N + n → 14 C + 1 H. The most ...
This table lists the mass and percent natural abundance for the stable nuclides. The mass of the longest lived isotope is given for elements without a stable nuclide.
Isotope abundances of carbon. In the above, the most intense ion is set to 100% since this corresponds best to the output from a mass spectrometer. This is not to be confused with the relative percentage isotope abundances which totals 100% for all the naturally occurring isotopes.
23 paź 2020 · Carbon isotopes are present in the atmosphere, ocean, and terrestrial biosphere in ratios of approximately 99% 12 C/C, 1% 13 C/C, and 1 × 10 −12 14 C/C. 12 C and 13 C are stable isotopes while 14 C is a radioactive isotope called radiocarbon.
For instance, the 6 proton carbon atom has three stable, naturally occurring isotopes: carbon-12 ([latex]\ce{_{6}^{12}C}[/latex]), carbon-13 ([latex]\ce{_{6}^{13}C}[/latex]) and carbon-14 ([latex]\ce{_{6}^{14}C}[/latex]), weighing 12, 13 and 14 amu respectively.
Since 1931, the Commission regularly publishes the critical evaluation of isotopic abundances of elements. These values form basis for the standard atomic weights of elements. Below is the current table of Isotopic Compositions of the Elements.
1 sty 2018 · Isotope ratio mass spectrometry (IRMS) provides measurements of the absolute abundance of stable carbon isotopes in natural or synthetic materials. Over the last few decades, advances in IRMS instrumentation now allow for accurate and highly precise stable carbon isotope measurements of bulk and molecular samples.
