Isotopes of barium

Naturally occurring barium (Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, recently identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks). This nuclide decays by double-electron capture (absorbing two electrons and emitting two neutrinos) with a half-life of (0.5-2.7)×10²¹ years (about 10¹¹ times the age of the universe).

There are a total of thirty-three known radioisotopes in addition to ¹³⁰Ba, but most of these are highly radioactive with half-lives in the several millisecond to several minute range. and thus never encountered in nature. The only notable exceptions are ¹³³Ba which has a half-life of 10.51 years, and ^137mBa (2.55 minutes), which is the decay product of ¹³⁷Cs (30.17 years, and a common fission product).

Barium-114 is the lightest nuclide known to undergo cluster decay, emitting a nucleus of stable ¹²C to produce ¹⁰²Sn in .0034% of decays.

Standard atomic mass: 137.327(7) u

¹¹²Ba is the heaviest known atom with equal numbers protons and neutrons. ¹⁰⁸Xe is the second-heaviest.

Table [edit]

1. ^ Bold for isotopes with half-lives longer than the age of the universe (nearly stable)
2. ^ Abbreviations:
   CD: Cluster decay
   EC: Electron capture
   IT: Isomeric transition
3. ^ Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe)
4. ^ Lightest nuclide known to undergo cluster decay
5. ^ Primordial radioisotope
6. ^ Believed to undergo β⁺β⁺ decay to ¹³²Xe with a half-life over 300×10¹⁸ years
7. ^ ^{a b c d e} Theoretically capable of spontaneous fission
8. ^ ^{a b c} Fission product

Notes [edit]

• 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.

See also [edit]

Book: Barium

References [edit]

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. 
• Half-life of ¹³⁰Ba from:
  • A. P. Meshik, C.M. Hohenberg, O.V. Pravdivtseva, and Ya.S. Kapusta (2001). "Weak decay of ¹³⁰Ba and ¹³²Ba: Geochemical measurements". Physical Review C 64 (3): 035205 [6 pages]. Bibcode:2001PhRvC..64c5205M. doi:10.1103/PhysRevC.64.035205. 
  • M. Pujol, B. Marty, P. Burnard and P. Philippot (2009). "Xenon in Archean barite: Weak decay of ¹³⁰Ba, mass-dependent isotopic fractionation and implication for barite formation". Geochimica et Cosmochimica Acta 73 (22): 6834–6846. Bibcode:2009GeCoA..73.6834P. doi:10.1016/j.gca.2009.08.002.