Isotopes of ruthenium

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Isotopes of ruthenium  (44Ru)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
96Ru5.54% stable
97Ru synth 2.9 d ε 97Tc
γ
98Ru1.87%stable
99Ru12.8%stable
100Ru12.6%stable
101Ru17.1%stable
102Ru31.6%stable
103Rusynth39.26 d β 103Rh
γ
104Ru18.6%stable
106Rusynth373.59 dβ 106Rh
Standard atomic weight Ar°(Ru)

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.

Contents

Twenty-four other radioisotopes have been characterized with atomic masses ranging from 86.95  Da (87Ru) to 119.95 Da (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 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 (39.26 days) and 106Ru (373.59 days). [5]

Ruthenium-96 Ruthenium-96.png
Ruthenium-96

List of isotopes

Nuclide
[n 1]
Z N Isotopic mass (Da) [7]
[n 2] [n 3]
Half-life [1]
[n 4]
Decay
mode
[1]
[n 5]
Daughter
isotope

[n 6]
Spin and
parity [1]
[n 7] [n 4]
Natural abundance (mole fraction)
Excitation energy [n 4] Normal proportion [1] Range of variation
85Ru444184.96712(54)#1# ms
[> 400 ns]
3/2−#
86Ru444285.95731(43)#50# ms
[> 400 ns]
0+
87Ru444386.95091(43)#50# ms
[> 1.5 μs]
1/2−#
88Ru444487.94166(32)#1.5(3) s β+ (>96.4%)88Tc0+
β+, p (<3.6%)87Mo
89Ru444588.937338(26)1.32(3) sβ+ (96.7%)89Tc(9/2+)
β+, p (3.1%)88Mo
90Ru444689.9303444(40)11.7(9) sβ+90Tc0+
91Ru444790.9267415(24)8.0(4) sβ+91Tc(9/2+)
91mRu [n 8] −340(500) keV7.6(8) sβ+ (>99.9%)91Tc(1/2−)
β+, p (?%)90Mo
92Ru444891.9202344(29)3.65(5) minβ+92Tc0+
92mRu2833.9(18) keV100(8) nsIT92Ru(8+)
93Ru444992.9171044(22)59.7(6) sβ+93Tc(9/2)+
93m1Ru734.40(10) keV10.8(3) sβ+ (78.0%)93Tc(1/2)−
IT (22.0%)93Ru
β+, p (0.027%)92Mo
93m2Ru2082.5(9) keV2.30(7) μsIT93Ru(21/2)+
94Ru445093.9113429(34)51.8(6) minβ+94Tc0+
94mRu2644.1(4) keV67.5(28) μsIT94Ru8+
95Ru445194.910404(10)1.607(4) hβ+95Tc5/2+
96Ru445295.90758891(18) Observationally Stable [n 9] 0+0.0554(14)
97Ru445396.9075458(30)2.8370(14) dβ+97Tc5/2+
98Ru445497.9052867(69)Stable0+0.0187(3)
99Ru445598.90593028(37)Stable5/2+0.1276(14)
100Ru445699.90421046(37)Stable0+0.1260(7)
101Ru [n 10] 4457100.90557309(44)Stable5/2+0.1706(2)
101mRu527.56(10) keV17.5(4) μsIT101Ru11/2−
102Ru [n 10] 4458101.90434031(45)Stable0+0.3155(14)
103Ru [n 10] 4459102.90631485(47)39.245(8) dβ103Rh3/2+
103mRu238.2(7) keV1.69(7) msIT103Ru11/2−
104Ru [n 10] 4460103.9054253(27)Observationally Stable [n 11] 0+0.1862(27)
105Ru [n 10] 4461104.9077455(27)4.439(11) hβ105Rh3/2+
105mRu20.606(14) keV340(15) nsIT105Ru5/2+
106Ru [n 10] 4462105.9073282(58)371.8(18) dβ106Rh0+
107Ru4463106.9099698(93)3.75(5) minβ107Rh(5/2)+
108Ru4464107.9101858(93)4.55(5) minβ108Rh0+
109Ru4465108.9133237(96)34.4(2) sβ109Rh(5/2+)
109mRu96.14(15) keV680(30) nsIT109Ru(5/2−)
110Ru4466109.9140385(96)12.04(17) sβ110Rh0+
111Ru4467110.917568(10)2.12(7) sβ111Rh5/2+
112Ru4468111.918807(10)1.75(7) sβ112Rh0+
113Ru4469112.922847(41)0.80(5) sβ113Rh(1/2+)
113mRu131(33) keV510(30) msβ (?%)113Rh(7/2−)
IT (?%)113Ru
114Ru4470113.9246144(38)0.54(3) sβ114Rh0+
115Ru4471114.929033(27)318(19) msβ115Rh(1/2+)
115mRu82(6) keV76(6) msβ (?%)115Rh(7/2−)
IT (?%)115Ru
116Ru4472115.9312192(40)204(6) msβ116Rh0+
117Ru4473116.93614(47)151(3) msβ117Rh3/2+#
117mRu185.0(4) keV2.49(6) μsIT117Ru7/2−#
118Ru4474117.93881(22)#99(3) msβ118Rh0+
119Ru4475118.94409(32)#69.5(20) msβ119Rh3/2+#
119mRu227.1(7) keV384(22) nsIT119Ru
120Ru4476119.94662(43)#45(2) msβ120Rh0+
121Ru4477120.95210(43)#29(2) msβ121Rh3/2+#
122Ru4478121.95515(54)#25(1) msβ122Rh0+
123Ru4479122.96076(54)#19(2) msβ123Rh3/2+#
124Ru4480123.96394(64)#15(3) msβ124Rh0+
125Ru4481124.96954(32)#12# ms
[> 550 ns]
3/2+#
This table header & footer:
  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. 1 2 3 #  Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  5. Modes of decay:
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  6. Bold symbol as daughter  Daughter product is stable.
  7. () spin value  Indicates spin with weak assignment arguments.
  8. Order of ground state and isomer is uncertain.
  9. Believed to undergo β+β+ decay to 96Mo with a half-life over 8×1019 years
  10. 1 2 3 4 5 6 Fission product
  11. Believed to undergo ββ decay to 104Pd

Alleged ruthenium-106 leak

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 was either in nuclear fuel cycle facilities or radioactive source production. In France levels up to 0.036mBq/m3 of air were measured. It was estimated that for distances of the order of a few tens of kilometres, contamination levels may have exceeded the limits for non-dairy foodstuffs. [8]

Asteroid which ended Cretaceous period

The ratios of the amounts of ruthenium isotopes were used to determine the age of the asteroid which exterminated the dinosaurs at the end of the Cretaceous period, and to show that it originated beyond Jupiter in the outer solar system. [9]

See also

Daughter products other than ruthenium

References

  1. 1 2 3 4 5 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. 1 2 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. Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  8. Detection of ruthenium 106 in France and in Europe, IRSN France (9 Nov 2017)
  9. Dunham, Will (15 August 2024). "Asteroid that doomed the dinosaurs originated beyond Jupiter". The Globe and Mail. Retrieved 8 July 2025. ruthenium shows distinct isotopic compositions between inner and outer solar system materials