Isotopes of uranium

Naturally occurring isotopes

This table shows information about naturally occuring isotopes, their atomic masses, their natural abundances, their nuclear spins, and their magnetic moments. Further data for radioisotopes (radioactive isotopes) of uranium are listed (including any which occur naturally) below.
Isotope Atomic mass (ma/u) Natural abundance (atom %) Nuclear spin (I) Magnetic moment (μ/μN)
234U 234.0409468 (24) [0.0055 (2)] 0 0
235U 235.0439242 (24) [0.7200 (51)] 7/2 -0.35
238U 238.0507847 (23) [99.2745 (106)] 0 0

Isotopic abundances of U
In the above picture, 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 total 100% for all the naturally occurring isotopes.

Radiosotope data

Further data for naturally occuring isotopes of uranium are listed above. This table gives information about some radiosotopes of uranium, their masses, their half-lives, their modes of decay, their nuclear spins, and their nuclear magnetic moments.
Isotope Mass Half-life Mode of decay Nuclear spin Nuclear magnetic moment
230U 230.03393 20.8 d α to 226Th 0
231U 231.03626 4.2 d α to 227Th 5/2
232U 232.03715 68.9 y α to 228Th 0
233U 233.039628 1.59 x 105 y α to 229Th; SF 5/2 0.59
234U 234.0409468 (24) 2.45 x 105 y α to 230Th; SF 0
235U 235.0439242 (24) 7.04 x 108 y α to 231Th; SF 7/2 0.38
236U 236.045561 2.34 x 107 y α to 232Th; SF 0
237U 237.048723 6.75 d β- to 237Np 1/2
238U 238.0507847 (23) 4.46 x 109 y α to 234Th; SF 0

Sheffield ChemPuter isotope pattern calculator

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  1. Naturally occurring isotope abundances: Commission on Atomic Weights and Isotopic Abundances report for the International Union of Pure and Applied Chemistry in Isotopic Compositions of the Elements 1989, Pure and Applied Chemistry, 1998, 70, 217. [Copyright 1998 IUPAC]
  2. For further information about radioisotopes see Jonghwa Chang's (Korea Atomic Energy Research Institute) Table of the Nuclides
  3. Masses, nuclear spins, and magnetic moments: I. Mills, T. Cvitas, K. Homann, N. Kallay, and K. Kuchitsu in Quantities, Units and Symbols in Physical Chemistry, Blackwell Scientific Publications, Oxford, UK, 1988. [Copyright 1988 IUPAC]

NMR Properties of uranium

Common reference compound: UF6 + 10% C6D6.

Table of NMR-active nucleus propeties of uranium
  Isotope 1 Isotope 2 Isotope 3
Isotope 233U 235U
Natural abundance /% 0.7200
Spin (I) 7/2
Frequency relative to 1H = 100 (MHz) 1.841000
Receptivity, DP, relative to 1H = 1.00 -
Receptivity, DC, relative to 13C = 1.00 -
Magnetogyric ratio, γ (107 rad T-1 s-1) -0.52
Magnetic moment, μ (μN) -0.43
Nuclear quadrupole moment, Q/millibarn 3663(8) 4936(6)
Line width factor, 1056l (m4) -


  1. R.K. Harris in Encyclopedia of Nuclear Magnetic Resonance, D.M. Granty and R.K. Harris, (eds.), vol. 5, John Wiley & Sons, Chichester, UK, 1996. I am grateful to Professor Robin Harris (University of Durham, UK) who provided much of the NMR data, which are copyright 1996 IUPAC, adapted from his contribution contained within this reference.
  2. J. Mason in Multinuclear NMR, Plenum Press, New York, USA, 1987. Where given, data for certain radioactive nuclei are from this reference.
  3. P. Pyykkö, Mol. Phys., 2008, 106, 1965-1974.
  4. P. Pyykkö, Mol. Phys., 2001, 99, 1617-1629.
  5. P. Pyykkö, Z. Naturforsch., 1992, 47a, 189. I am grateful to Professor Pekka Pyykkö (University of Helsinki, Finland) who provided the nuclear quadrupole moment data in this and the following two references.
  6. D.R. Lide, (ed.), CRC Handbook of Chemistry and Physics 1999-2000 : A Ready-Reference Book of Chemical and Physical Data (CRC Handbook of Chemistry and Physics, CRC Press, Boca Raton, Florida, USA, 79th edition, 1998.
  7. P. Pyykkö, personal communication, 1998, 204, 2008, 2010.
  8. The isotopic abundances are extracted from the naturally occurring isotopes section within WebElements.

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uranium atomic number