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Isotopes of Hydrogen

List, data and properties of all known isotopes of Hydrogen as well as radioactive decay products and intermediate products.


Hydrogen isotopes

In nature, the chemical element hydrogen occurs in the form of the three isotopes 1H (protium), 2H (deuterium, D) and 3H (tritium, T) on. Other unstable nuclides 4H to 7H were artificially created [d, e, f, g, h].

Natural hydrogen is thus a isotopic mixture of protium (99.985%), deuterium (0.015%) and a negligible proportion of tritium:


Naturally Occurring Hydrogen Isotopes

Atomic Mass maQuantityHalf-lifeSpin
Isotopic mixture
1,008 u100 %
Isotope 1H1,0078250322(6) u99,99 %stable1/2+
Isotope 2H2,0141017781(8) u0,01 %stable1+
Isotope 3H3,01604928132(8) utraces12.32(2) a1/2+




Protium or light hydrogen refers to isotopically pure hydrogen-1, 1H. The nucleus consists of only one proton, with no neutrons, and is the most common type of atom in the universe.



Deuterium or heavy hydrogen (formerly also: diplogen) is - besides protium - a stable hydrogen isotope with a neutron in the nucleus. The deuterium content of hydrogen on Earth varies in the range from 0.0026 to 0.0184 atomic percent.



Tritium (also: superheavy hydrogen; superheavy hydrogen) is a radioisotope that only occurs in traces. The occurrence is estimated at 1 tritium atom per 1017 protium atoms. On Earth, tritium is found mainly in the atmosphere and in the water of the oceans, formed by the interaction of cosmic rays with atoms in the Earth's atmosphere, e.g.:

14N + n → 12C + 3H.

Artificially, tritium can be produced by neutron activation of lithium-6

6Li + n → 4He + 3H + 4,78 MeV

as well as by neutron capture from deuterium in heavy water reactors. In addition, but in low concentrations, tritium occurs as a decomposition product of 3He and in certain fusion reactions.

Tritium decays to 2He, emitting an electron and an antineutrino; E0 = 18.57 keV.


Artificial hydrogen isotopes

The hydrogen isotopes H-4 to H-7, which are not found in nature, are all very short-lived and were artificially produced [d, e, f, g, h:] - e.g.:

* 4H - by bombarding tritium with fast deuterium nuclei,

* 5H - by bombarding tritium with fast tritium cores and

* 7H - by bombarding hydrogen with helium-8 atoms


Quadium is a name coined in the literature for hydrogen-4 [i].


Isotope Table: Hydrogen


Atomic Properties

ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
1H110Hydrogen-11.0078250322(6) u
[1.0072765 u]
{7.28897 MeV}
1/2++ 2.792847351(9)9B
2H121Hydrogen-22.0141017781(8) u
[2.0135532 u]
{13.13572 MeV}
1++ 0.857438231(5)
3H132Hydrogen-33.01604928132(8) u
[3.0155007 u]
{14.94981 MeV}
1/2++ 2.978962460(14)4H
4H143Hydrogen-44.02643(11) u
[4.0258814 u]
{24.61939 MeV}
5H154Hydrogen-55.03531(10) u
[5.0347614 u]
{32.89105 MeV}
6H165Hydrogen-66.04496(27) u
[6.0444114 u]
{41.87997 MeV}
7H176Hydrogen-77.05275(108) u
[7.0522014 u]
{49.13631 MeV}


Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
H-312.32(2) aβ-3He100 %0.018592(0) MeVAL
H-41.39 × 10-22 sn → 3H100 %23.51(11) MeVAL
H-58.61 × 10-23 sn → 4H100 %25.44(95) MeVAL
H-62.94 × 10-22 sn 5H100 %24.280 MeVAL
H-75.07 × 10-21 s4n → 3HAL


Notes (related to the columns):

1 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Hydrogen isotope.
6 - Relative atomic mass of the Hydrogen isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
7 - Nuclear spin I, unit: h/2π.
8 - Nuclear magnetic moment μmag.
9 - Source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.
10 - Decay: Half-live of the Hydrogen isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
11 - Decay: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
12 - Decay percentage in percent (%).
13 - Decay energy; Particle energy related to decay type.
14 - AE = Excitation energy for metastable nuclei.
15 - Other information and notes: AL = Adopted Levels (link to external data [1]).


()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.


NMR active Hydrogen nuclides

quantity 1)
Nuclear magnetic
107 rad T-1 s-1
Q fm-2
v0 bei 1 T
H0 = const.
v0 = const. 2)
99,99 %
+ 2,792847351(9)26,67522242,57591,00000
0,01 %
+ 0,857438231(5)4,10660,285783(30)6,53590,00965
+ 2,978962460(14)28,53545,41481,21354

1) Quantity Percentage of natural occurrence.

2) Related to 1H = 1,000.


Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Hydrogen radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
H-3109 Bq100 Bq/g2000 TBq100 Bq/cm2-12.3 a

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)


Literature Sources and References

Properties of the Hydrogen nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Hydrogen: NMR properties - 1H-NMR, 2H-NMR, 3H-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

[9] - NN:
Wasserstoff-Isotopentrennung mit MOFs.
In: Internetchemie News, (2017), DOI https://www.internetchemie.info/news/2017/mar17/mof-wasserstoff-isotopentrennung.php.


Category: Isotopes

Last update: 05.07.2020

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