Isotopes of ruthenium

Nuclides with atomic number of 44 but with different mass numbers

Naturally occurring ruthenium (₄₄Ru) is composed of seven stable isotopes (of which two may in the future be found radioactive). Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are ¹⁰⁶Ru, with a half-life of 373.59 days; ¹⁰³Ru, with a half-life of 39.26 days and ⁹⁷Ru, with a half-life of 2.9 days.

Twenty-four other radioisotopes have been characterized with atomic weights ranging from 86.95 u (⁸⁷Ru) to 119.95 u (¹²⁰Ru). Most of these have half-lives that are less than five minutes, except ⁹⁴Ru (half-life: 51.8 minutes), ⁹⁵Ru (half-life: 1.643 hours), and ¹⁰⁵Ru (half-life: 4.44 hours).

The primary decay mode before the most abundant isotope, ¹⁰²Ru, is electron capture and the primary mode after is beta emission. The primary decay product before ¹⁰²Ru is technetium and the primary product after is rhodium.

Because of the very high volatility of ruthenium tetroxide (RuO
₄) ruthenium radioactive isotopes with their relative short half-life are considered as the second most hazardous gaseous isotopes after iodine-131 in case of release by a nuclear accident.^[4][5][6] The two most important isotopes of ruthenium in case of nuclear accident are these with the longest half-life: ¹⁰³Ru (39.26 days) and ¹⁰⁶Ru (373.59 days).^[5]

List of isotopes

1. ^mRu – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. Modes of decay:
6. Bold symbol as daughter – Daughter product is stable.
7. ( ) spin value – Indicates spin with weak assignment arguments.
8. Believed to undergo β⁺β⁺ decay to ⁹⁶Mo with a half-life over 6.7×10¹⁶ years
9. Fission product
10. Believed to undergo β⁻β⁻ decay to ¹⁰⁴Pd

• 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.^{[citation needed]}
• In September 2017 an estimated amount of 100 to 300 TBq (0.3 to 1 g) of ¹⁰⁶Ru was released in Russia, probably in the Ural region. It was, after ruling out release from a reentering satellite, concluded that the source is to be found either in nuclear fuel cycle facilities or radioactive source production. In France levels up to 0.036mBq/m³ of air were measured. It is estimated that over distances of the order of a few tens of kilometres around the location of the release levels may exceed the limits for non-dairy foodstuffs.^[7]

Ruthenium-96

References

1. Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
2. "Standard Atomic Weights: Ruthenium". CIAAW. 1983.
3. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
4. Ronneau, C., Cara, J., & Rimski-Korsakov, A. (1995). Oxidation-enhanced emission of ruthenium from nuclear fuel. Journal of Environmental Radioactivity, 26(1), 63-70.
5. Backman, U., Lipponen, M., Auvinen, A., Jokiniemi, J., & Zilliacus, R. (2004). Ruthenium behaviour in severe nuclear accident conditions. Final report (No. NKS–100). Nordisk Kernesikkerhedsforskning.
6. Beuzet, E., Lamy, J. S., Perron, H., Simoni, E., & Ducros, G. (2012). Ruthenium release modelling in air and steam atmospheres under severe accident conditions using the MAAP4 code^{[dead link]}. Nuclear Engineering and Design, 246, 157-162.
7. [1] Detection of ruthenium 106 in France and in Europe, IRSN France (9 Nov 2017)

• Isotope masses from:
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (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:
  • de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
  • Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
• "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
• Half-life, spin, and isomer data selected from the following sources.
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (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.x database". Brookhaven National Laboratory.
  • Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.