Carbon-12

Properties and data of the isotope ¹²C.

Contents

General Data

Parent Nuclides

Isotones und Isobares

See also: List of individual Carbon isotopes (and general data sources).

General data

Name of the isotope:Carbon-12; C-12Symbol:¹²C or 126CMass number A:12 (= number of nucleons)Atomic number Z:6 (= number of protons)Neutrons N:6Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1 (= neutron-proton ratio)Neutron excess (N-Z):0Isotopic mass:12.00000000000 u (atomic weight of Carbon-12)Nuclide mass:11.9967085 u (calculated nuclear mass without electrons)Mass excess:0 MeVMass defect:0.098939688000002 u (per nucleus)Nuclear binding energy:92.16172573 MeV (per nucleus)
7.68014381 MeV (average binding energy per nucleon)Separation energy:S_N = 18.72072(6) MeV (first neutron)
S_P = 15.956679(12) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Quadrupole moment Q:+0.0100(9) barn (100 fm²)Charge radius:2.4702(22) femtometer fmYear of discovery:1919

Parent Nuclides

Direct parent isotopes are: ¹²B, ¹²N.

Occurrence

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

	Atomic Mass m_a	Quantity	Half-life	Spin
Carbon Isotopic mixture	12.011 u	100 %
Isotope ¹²C	12.00000000000 u	98.94 % [98.84 - 99.04 %]	stable	0+
Isotope ¹⁴C	14.003241988(4) u	[trace]	5700(30) years	0+
Isotope ¹³C	13.003354835(2) u	1.06 % [0.96 - 1.16 %]	stable	1/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 6) and isobaric (same nucleon number A = 12) with Carbon-12. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.