Isotopes of sodium

There are twenty recognized isotopes of sodium ranging from ¹⁸Na to ³⁷Na and two isomers (^22mNa and ^24mNa). ²³Na is the only stable (and the only primordial) isotope. As such, it is considered a monoisotopic element and it has a standard atomic mass: 22.98976928(2) u. Sodium has two radioactive cosmogenic isotopes (²²Na, half-life = 2.605 years; and ²⁴Na, half-life ≈ 15 hours). With the exception of those two, all other isotopes have half-lives under a minute, most under a second. The least stable is ¹⁸Na, with a half-life of 1.3*10^-21 (4) seconds.

Acute neutron radiation exposure (e.g., from a nuclear criticality accident) converts some of the stable ²³Na in human blood plasma to ²⁴Na. By measuring the concentration of this isotope, the neutron radiation dosage to the victim can be computed.

²²Na is a positron-emitting isotope with a remarkably long half-life. It is used to create test-objects and point-sources for Positron emission tomography.

Table

1. ^ Abbreviations:
   IT: Isomeric transition
2. ^ Bold for stable isotopes
3. ^ ^{a b} Cosmogenic nuclide

Notes

• 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

• 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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf. 
• 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. http://www.iupac.org/publications/pac/75/6/0683/pdf/. 
  • 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. http://iupac.org/publications/pac/78/11/2051/pdf/. 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. http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf. 
  • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. http://www.nndc.bnl.gov/nudat2/. 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 978-0849304859. 

External links

• Sodium isotopes data from The Berkeley Laboratory Isotopes Project's

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