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Properties and data of the isotope 13C.



Carbon-13 isotope

Carbon-13 - 13C or C-13 - is a natural, stable isotope of the chemical element carbon, whose atomic nucleus consists of six protons and seven neutrons. As one of the environmental isotopes, it accounts for about 1.1% of all natural carbon on Earth.

Pure carbon-13 for commercial use - particularly for the chemical synthesis of 13 C-labeled compounds - must be enriched due to its natural abundance of approximately one 1%. In principle, various techniques or methods such as thermal diffusion, chemical exchange, gas diffusion as well as laser and cryogenic distillation are available to separate C-13 from the main component C-12 of natural carbon.

At present, however, only the cryogenic distillation of methane or carbon monoxide is an economically viable industrial production technology, although such carbon-13 production facilities represent a significant investment. Cryogenic distillation columns more than 100 meters high are required to separate the compounds containing carbon-12 or carbon-13. The world's largest reported commercial C-13 plant (CIL plant in Ohio) has a production capacity of approximately 420 kg of carbon-13 per year (2019). In this method, natural carbon monoxide (CO) is liquefied at a very low temperature and then distilled through special stainless steel columns several kilometers long. In comparison, a 1969 pilot plant for the cryogenic distillation of carbon monoxide at Los Alamos Scientific Laboratories (USA) was able to produce about 4 kg of carbon-13 annually.

See also: list of Carbon isotopes.


General data

Name of the isotope:Carbon-13; C-13Symbol:13C or 136CMass number A:13 (= number of nucleons)Atomic number Z:6 (= number of protons)Neutrons N:7Isotopic mass:13.003354835(2) u (atomic weight of Carbon-13)Nuclide mass:13.0000634 u (calculated nuclear mass without electrons)Mass excess:3.12501 MeVMass defect:0.104249769 u (per nucleus)Nuclear binding energy:97.10803432 MeV (per nucleus)
7.46984879 MeV (average binding energy per nucleon)
Separation energy:SN = 4.94631(0) MeV (first neutron)
SP = 17.5334(13) MeV (first proton)
Half-life:stableSpin and parity:
(nuclear angular momentum)
1/2-Isobaric spin: 1/2Magnetic dipole moment:μ(μN) = + 0.702369(4)Charge radius:2.4614(34) femtometer fmMatter radius:3.324 femtometer fmMirror nucleus:Nitrogen-13Year of discovery:1929


Parent Nuclides

Direct parent isotopes are: 13B, 13N.



Comparison of the natural Carbon isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):


Atomic Mass maQuantityHalf-lifeSpin
Isotopic mixture
12.011 u100 %
Isotope 12C12.00000000000 u98.94 %
[98.84 - 99.04 %]
Isotope 14C14.003241988(4) u
5700(30) a0+
Isotope 13C13.003354835(2) u1.06 %
[0.96 - 1.16 %]


NMR data

Nuclear magnetic properties of the NMR active Nuclide 13C

Isotope:13C-NMRQuantity:1.06 % [0.96 - 1.16 %]Spin:1/2-Nuclearmagnetic moment
+ 0.702369(4)Gyromagnetic ratio γ:6.7283 · 107 rad T-1 s-1Nuclear g-factor:gl = 1.404738Resonance frequency:v0 = 10.7084 at 1 TRelative Sensitivity:0.01591 (H0 = const.)
0.2515 (v0 = const.)
[related to 1H = 1.000]


Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 7) and isobaric (same nucleon number A = 13) with Carbon-13. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.


OZIsotone N = 7Isobar A = 13


External data and identifiers

CAS:14762-74-4InChI Key:OKTJSMMVPCPJKN-OUBTZVSYSA-NSMILES:[13C]Adopted Levels, Gammas:NuDat 13C


Literature and References

[1] - Darren Brown, John Greene:
10th international symposium on the synthesis and applications of isotopes and isotopically labelled compounds.
In: Journal of Labelled Compounds and Radiophamaceuticals, (2010), DOI 10.1002/jlcr.1775.

[2] - Hu-LinLi, Yong-Lin Ju, Liang-JunLi, Da-GangXu:
Separation of isotope 13C using high-performance structured packing.
In: Chemical Engineering and Processing: Process Intensification, (2010), DOI 10.1016/j.cep.2010.02.001.


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Last update: 2023-11-09

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