Isotopes of ruthenium

Isotopes of ruthenium (44Ru)
Main isotopes[1] Decay
abun­dance half-life (t1/2) mode pro­duct
96Ru 5.54% stable
97Ru synth 2.837 d ε 97Tc
98Ru 1.87% stable
99Ru 12.8% stable
100Ru 12.6% stable
101Ru 17.1% stable
102Ru 31.6% stable
103Ru synth 39.245 d β 103Rh
104Ru 18.6% stable
106Ru synth 371.8 d β 106Rh
Standard atomic weight Ar°(Ru)

Naturally occurring ruthenium (44Ru) is composed of seven stable isotopes: 96, 98-102, 104 (of which the first and last may in the future be found radioactive). Additionally, 27 synthetic radioactive isotopes have been discovered. Of these radioisotopes, the most stable are 106Ru with a half-life of 371.8 days or 1.018 years, 103Ru, with a half-life of 39.245 days, and 97Ru with a half-life of 2.837 days.

The other known isotopes run from 87Ru to 120Ru, and most of these have half-lives that are less than five minutes, except 94Ru (51.8 minutes), 95Ru (1.607 hours), and 105Ru (4.44 hours).

The primary decay mode before the most abundant isotope, 102Ru, is electron capture to isotopes of technetium, and after beta emission to isotopes of rhodium. Double beta decay is the allowed mode for the two observationally stable isotopes: 96Ru and 104Ru.

Because of the volatility of ruthenium tetroxide (RuO
4
), ruthenium isotopes with relatively short half-life are considered the next most hazardous airborne isotopes, after iodine-131, in case of release by a nuclear accident.[4][5][6] The two most important isotopes of ruthenium so released are those with the longest half-life: 103Ru 106Ru.[5]

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  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. ^ a b 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. Nuclear Engineering and Design, 246, 157-162.