Isotopes of europium

Europium has two stable isotopes and both are used for the production of radioisotopes. Eu-151 is used for the production of Eu-152 which is used as a reference source in gammaspectroscopy. Eu-153 can be used for the production of high specific activity Sm-153 via fast neutron irradiation. Europium isotopes can be obtained from Trace Sciences International.

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 europium are listed (including any which occur naturally) below.
Isotope Atomic mass (ma/u) Natural abundance (atom %) Nuclear spin (I) Magnetic moment (μ/μN)
151Eu 150.919702 (8) 47.81 (3) 5/2 3.4718
153Eu 152.921225 (4) 52.19 (3) 5/2 1.5331

Isotopic abundances of Eu
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 europium are listed above. This table gives information about some radiosotopes of europium, 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
145Eu 144.916263 5.93 d EC to 145Sm 5/2 3.99
146Eu 145.91720 4.57 d EC to 146Sm 4 1.43
147Eu 146.916742 24.4 d EC to 147Sm; α to 143Pm 5/2 3.72
148Eu 147.91815 54.5 d EC to 148Sm; α to 143Pm 5 2.34
149Eu 148.91792 93.1 d EC to 149Sm 5/2 3.57
150Eu 149.91970 36 y EC to 150Sm 5 2.71
152Eu 151.921741 13.5 y EC to 152Sm; β- to 152Gd 3 -1.91
154Eu 153.922976 8.59 y EC to 154Sm; β- to 154Gd 3 2.000
155Eu 154.922890 4.76 y β- to 155Gd 5/2 1.6
156Eu 155.92475 15.2 d β- to 156Gd 3 -2.01

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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 europium

Common reference compound: .

Table of NMR-active nucleus propeties of europium
  Isotope 1 Isotope 2 Isotope 3
Isotope 151Eu 153Eu
Natural abundance /% 47.8 52.2
Spin (I) 5/2 5/2
Frequency relative to 1H = 100 (MHz) about 24.86 about 10.98
Receptivity, DP, relative to 1H = 1.00 - -
Receptivity, DC, relative to 13C = 1.00 - -
Magnetogyric ratio, γ (107 rad T-1 s-1) 6.6510 2.9369
Magnetic moment, μ (μN) 4.1078 1.8139
Nuclear quadrupole moment, Q/millibarn 903(10) 2412(21)
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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europium atomic number