Curium: isotope data

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 curium are listed (including any which occur naturally) below.
Isotope Mass / Da Natural abundance (atom %) Nuclear spin (I) Magnetic moment (μ/μN)

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 curium are listed above. This table gives information about some radiosotopes of curium, 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
240Cm 240.05552 27 h α to 236Pu; EC to 240Am; SF 0
241Cm 241.05765 32.8 d α to 237Pu; EC to 241Am 1/2
242Cm 242.05883 162.8 d α to 238Pu; SF 0
243Cm 243.06138 28.5 y α to 239Pu; EC to 243Am 5/2 0.41
244Cm 244.06275 18.11 y α to 240Pu; SF 0
245Cm 245.06548 8500 y α to 241Pu; SF 7/2 0.5
246Cm 246.06722 4780 y α to 242Pu; SF 0
247Cm 247.070347 (5) 1.56 x 107 y α to 243Pu 9/2 0.37
248Cm 248.07234 3.4 x 105 y α to 244Pu; SF 0
249Cm 249.07595 64.15 m β- to 249Bk 1/2
250Cm 250.07835 9700 y α to 246Pu; β- to 250Bk; SF 0

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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 curium

Common reference compound: .

Table of NMR-active nucleus propeties of curium
  Isotope 1 Isotope 2 Isotope 3
Isotope 247Cm
Natural abundance /% 0
Spin (I) 9/2
Frequency relative to 1H = 100 (MHz) 0.75
Receptivity, DP, relative to 1H = 1.00 -
Receptivity, DC, relative to 13C = 1.00 -
Magnetogyric ratio, γ (107 rad T‑1 s-1) 0.20
Magnetic moment, μ (μN)
Nuclear quadrupole moment, Q/millibarn -
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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