Iron: isotope data

Iron isotopes are mainly used in nutritional studies, with Fe-57 and Fe-58 being the two most commonly used Fe isotopes. Studies have included iron-loss by human adolescents, conditions for effective iron absorption, interventions for anemia and genetic iron control. The Fe-54 isotope is used for the production of radioactive Fe-55 which in turn is used as an electron capture detector and in X-ray fluorescence. Fe-56 can be used for the production of radioactive Co-55 which is used as a tumor seeking agent in bleomycin.

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 iron are listed (including any which occur naturally) below.
Isotope Mass / Da Natural abundance (atom %) Nuclear spin (I) Magnetic moment (μ/μN)
54Fe 53.9396127 (15) 5.845 (35) 0
56Fe 55.9349393 (16) 91.754 (36) 0
57Fe 56.9353958 (16) 2.119 (10) 1/2 0.09062294
58Fe 57.9332773 (16) 0.282 (4) 0

In the above, 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 totals 100% for all the naturally occurring isotopes.

Radiosotope data

Further data for naturally occuring isotopes of iron are listed above. This table gives information about some radiosotopes of iron, their masses, their half-lives, their modes of decay, their nuclear spins, and their nuclear magnetic moments.
Isotope Mass / Da Half-life Mode of decay Nuclear spin Nuclear magnetic moment
52Fe 51.94812 8.28 h EC to 52Mn 0
53Fe 52.945312 8.51 m EC to 53Mn 7/2
55Fe 54.938298 2.73 y EC to 55Mn 3/2
59Fe 58.934880 44.51 d β- to 59Co 3/2 0.29
60Fe 59.934077 1.5 x 106 y β- to 60Co 0
61Fe 60.93675 6.0 m β- to 61Co
62Fe 61.93677 68 s β- to 62Co 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 iron

Common reference compound: Fe(CO)5/C6D6.

Table of NMR-active nucleus propeties of iron
  Isotope 1 Isotope 2 Isotope 3
Isotope 57Fe
Natural abundance /% 2.2
Spin (I) 1/2
Frequency relative to 1H = 100 (MHz) 3.237778
Receptivity, DP, relative to 1H = 1.00 0.000000752
Receptivity, DC, relative to 13C = 1.00 0.00430
Magnetogyric ratio, γ (107 rad T‑1 s-1) 0.8680624
Magnetic moment, μ (μN) 0.1569636
Nuclear quadrupole moment, Q/millibarn 160
Line width factor, 1056 l (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.

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