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Isotopes of Hydrogen

List, data and properties of all known isotopes of Hydrogen.


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 3H3,01604928132(8) utraces12.32(2) a1/2+
Isotope 1H1,0078250322(6) u99,99 %stable1/2+
Isotope 2H2,0141017781(8) u0,01 %stable1+




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

The two following tables list the most important data and properties of the Hydrogen isotopes. Further information on the individual Hydrogen isotopes is listed on separate pages and can be accessed via the link in column 1.


Atomic Properties

ENAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
Hydrogen-111H01.0078250322(6) u
[1.0072765 u]
{7.28897 MeV}
Hydrogen-221H12.0141017781(8) u
[2.0135532 u]
{13.13572 MeV}
Hydrogen-331H23.01604928132(8) u
[3.0155007 u]
{14.94981 MeV}
Hydrogen-441H34.02643(11) u
[4.0258814 u]
{24.61939 MeV}
Hydrogen-551H45.03531(10) u
[5.0347614 u]
{32.89105 MeV}
Hydrogen-661H56.04496(27) u
[6.0444114 u]
{41.87997 MeV}
Hydrogen-771H67.05275(108) u
[7.0522014 u]
{49.13631 MeV}


Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
H-312.32(2) aβ-3He100 %0.018592(0) MeVAL
H-413.9 zsn → 3H100 %23.51(11) MeVAL
H-5861 zs2n → 3H100 %22.396(89) MeVAL
H-629.4 zsn 5H100 %24.280 MeVAL
H-765.2 zs4n → 3HAL


Notes (related to the columns):

1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and Atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - 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.
5 - nuclear spin I, unit: h/2π.
6 - 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.

7 - isotope notation in short form.
8 - decay: half-live of the Hydrogen isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: 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.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - 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)
Gyromagnetic ratio
{Quadrupole moment}
v0 bei 1 T
H0 = const.
v0 = const. 3)
99,99 %
0,01 %
+ 0,857438231(5)4,1066
+ 2,978962460(14)28,535

1) Quantity Percentage of natural occurrence.

2) Gyromagnetic ratio: 107 rad T-1 s-1
    Quadrupole moment: Q [barn] = [100 fm2]

3) 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).


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Last update: 2022-12-20

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