Isotopes of neodymium

Naturally occurring neodymium (Nd) is composed of 5 stable isotopes, ¹⁴²Nd, ¹⁴³Nd, ¹⁴⁵Nd, ¹⁴⁶Nd and ¹⁴⁸Nd, with ¹⁴²Nd being the most abundant (27.2% natural abundance), and 2 radioisotopes, ¹⁴⁴Nd and ¹⁵⁰Nd. In all, 33 radioisotopes of Neodymium have been characterized up to now, with the most stable being naturally occurring isotopes ¹⁴⁴Nd (alpha decay, a half-life (T_½) of 2.29×10¹⁵ years) and ¹⁵⁰Nd (double beta decay, T_½ of 7×10¹⁸ years). All of the remaining radioactive isotopes have half-lives that are less than 11 days, and the majority of these have half-lives that are less than 70 seconds. This element also has 13 known meta states with the most stable being ^139mNd (T_½ 5.5 hours), ^135mNd (T_½ 5.5 minutes) and ^133m1Nd (T_½ ~70 seconds).

The primary decay modes before the most abundant stable isotope, ¹⁴²Nd, are electron capture and positron decay, and the primary mode after is beta minus decay. The primary decay products before ¹⁴²Nd are element Pr (praseodymium) isotopes and the primary products after are element Pm (promethium) isotopes.
Standard atomic mass: 144.242(3) u

Table

1. ↑ Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
2. ↑ Abbreviations:
   EC: Electron capture
   IT: Isomeric transition
3. ↑ Bold for stable isotopes
4. ↑ Theoretically capable of Spontaneous fission
5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Fission product
6. ↑ Used in Samarium-neodymium dating
7. ↑ Theorized to undergo α decay to ¹³⁹Ce
8. ↑ 8.0 8.1 Primordial radionuclide
9. ↑ Theorized to undergo α decay to ¹⁴¹Ce with a half-life over 6×10¹⁶ years
10. ↑ Theorized to undergo α decay to ¹⁴²Ce
11. ↑ Theorized to undergo α decay to ¹⁴⁴Ce with a half-life over 3.0×10¹⁸ years

Notes

• Evaluation of isotopic composition is for most but not all commercial samples.
• Geologically exceptional samples are known in which the isotopic composition lies outside the reported range. The uncertainty in the atomic mass may exceed the stated value for such specimens.
• Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
• Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

1. ↑ http://www.nucleonica.net/unc.aspx

• Isotope masses from:
  • G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. 
• Isotopic compositions and standard atomic masses from:
  • J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683. 
  • M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary. 
• Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
  • G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. 
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. 
  • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.