Isotopes of selenium

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Isotopes of selenium  (34Se)
Main isotopes [1] Decay
abun­dance half-life (t1/2) mode pro­duct
72Se synth 8.4 d ε 72As
γ –
74Se0.860% stable
75Sesynth119.8 dε 75As
γ–
76Se9.23%stable
77Se7.60%stable
78Se23.7%stable
79Se trace 3.27×105 y β− 79Br
80Se49.8%stable
82Se8.82%8.76×1019 y β−β− 82Kr
Standard atomic weight Ar°(Se)

Selenium (34Se) has six natural isotopes that occur in significant quantities, along with the trace isotope 79Se, which occurs in minute quantities in uranium ores. Five of these isotopes are stable: 74Se, 76Se, 77Se, 78Se, and 80Se. The last three also occur as fission products, along with 79Se, which has a half-life of 327,000 years, [4] [5] and 82Se, which has a very long half-life (~1020 years, decaying via double beta decay to 82Kr) and for practical purposes can be considered to be stable. There are 23 other unstable isotopes that have been characterized, the longest-lived being 79Se with a half-life 327,000 years, 75Se with a half-life of 120 days, and 72Se with a half-life of 8.40 days. Of the other isotopes, 73Se has the longest half-life, 7.15 hours; most others have half-lives not exceeding 38 seconds.

Contents

List of isotopes

Nuclide
[n 1] 		Z N Isotopic mass (Da) [6]
[n 2] [n 3] 		Half-life [1]
[n 4] [n 5] 		Decay
mode [1]
[n 6] 		Daughter
isotope
[n 7] 		Spin and
parity [1]
[n 8] [n 5] 		Natural abundance (mole fraction)
Excitation energyNormal proportion [1] Range of variation
63Se342962.98191(54)#13.2(39) ms β+, p (89%)62Ge3/2−#
β+ (11%)63As
2p? (<0.5%)61Ge
64Se343163.97117(54)#22.6(2) msβ+?64As0+
β+, p?63Ge
65Se343164.96455(32)#34.2(7) msβ+, p (87%)64Ge3/2−#
β+ (13%)65As
66Se343265.95528(22)#54(4) msβ+66As0+
β+, p?65Ge
67Se343366.949994(72)133(4) msβ+ (99.5%)67As5/2−#
β+, p (0.5%)66Ge
68Se343467.94182524(53)35.5(7) sβ+68As0+
69Se343568.9394148(16)27.4(2) sβ+ (99.95%)69As1/2−
β+, p (.052%)68Ge
69m1Se38.85(22) keV2.0(2) μs IT 69Se5/2−
69m2Se574.0(4) keV955(16) nsIT69Se9/2+
70Se343669.9335155(17)41.1(3) minβ+70As0+
71Se343770.9322094(30)4.74(5) minβ+71As(5/2−)
71m1Se48.79(5) keV5.6(7) μsIT71Se(1/2−)
71m2Se260.48(10) keV19.0(5) μsIT71Se(9/2+)
72Se343871.9271405(21)8.40(8) d EC 72As0+
73Se343972.9267549(80)7.15(9) hβ+73As9/2+
73mSe25.71(4) keV39.8(17) minIT (72.6%)73Se3/2−
β+ (27.4%)73As
74Se344073.922475933(15) Observationally Stable [n 9] 0+0.0086(3)
75Se344174.922522870(78)119.78(3) dEC75As5/2+
76Se344275.919213702(17)Stable0+0.0923(7)
77Se344376.919914150(67)Stable1/2−0.0760(7)
77mSe161.9223(10) keV17.36(5) sIT77Se7/2+
78Se344477.91730924(19)Stable0+0.2369 (22)
79Se [n 10] 344578.91849925(24)3.27(28)×105 yβ−79Br7/2+
79mSe95.77(3) keV3.900(18) minIT (99.94%)79Se1/2−
β− (0.056%)79Br
80Se344679.9165218(10)Observationally Stable [n 11] 0+0.4980(36)
81Se344780.9179930(10)18.45(12) minβ−81Br1/2−
81mSe103.00(6) keV57.28(2) minIT (99.95%)81Se7/2+
β− (.051%)81Br
82Se [n 12] 344881.91669953(50)8.76(15)×1019 y β−β− 82Kr0+0.0882(15)
83Se344982.9191186(33)22.25(4) minβ−83Br9/2+
83mSe228.92(7) keV70.1(4) sβ−83Br1/2−
84Se345083.9184668(21)3.26(10) minβ−84Br0+
85Se345184.9222608(28)32.9(3) sβ−85Br(5/2)+
86Se345285.9243117(27)14.3(3) sβ−86Br0+
β−, n?85Br
87Se345386.9286886(24)5.50(6) sβ− (99.50%)87Br(3/2+)
β−, n (0.60%)86Br
88Se345487.9314175(36)1.53(6) sβ− (99.01%)88Br0+
β−, n (0.99%)87Br
89Se345588.9366691(40)430(50) msβ− (92.2%)89Br5/2+#
β−, n (7.8%)88Br
90Se345689.94010(35)210(80) msβ−90Br0+
β−, n?89Br
91Se345790.94570(47)270(50) msβ− (79%)91Br1/2+#
β−, n (21%)90Br
β−, 2n?89Br
92Se345891.94984(43)#90# ms [>300 ns]β−?92Br0+
β−, n?91Br
β−, 2n?90Br
92mSe3072(2) keV15.7(7) μsIT92Se(9−)
93Se345992.95614(43)#130# ms [>300 ns]β−?93Br1/2+#
β−, n?92Br
β−, 2n?91Br
93mSe678.2(7) keV420(100) nsIT93Se
94Se346093.96049(54)#50# ms [>300 ns]β−?94Br0+
β−, n?93Br
β−, 2n?92Br
94mSe2430.0(6) keV680(50) nsIT94Se(7−)
95Se346194.96730(54)#70# ms [>400 ns]β−?95Br3/2+#
β−, n?94Br
β−, 2n?93Br
96Se [7] 3462
97Se [7] 3463
This table header & footer:
  1. ↑ mSe – 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. ↑ Bold half-life – nearly stable, half-life longer than age of universe.
  5. 1 2 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ↑ Modes of decay:
    EC: Electron capture
    IT: Isomeric transition
    n: Neutron emission
    p: Proton emission
  7. ↑ Bold symbol as daughter – Daughter product is stable.
  8. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  9. ↑ Believed to decay by β+β+ to 74Ge with a half-life over 2.3×1018 y.
  10. ↑ Long-lived fission product
  11. ↑ Believed to decay by β−β− to 80Kr
  12. ↑ Primordial radionuclide

Use of radioisotopes

The isotope selenium-75 has radiopharmaceutical uses. For example, it is used in high-dose-rate endorectal brachytherapy, as an alternative to iridium-192. [8]

In paleobiogeochemistry, the ratio in amount of selenium-82 to selenium-76 (i.e, the value of δ82/76Se) can be used to track down the redox conditions on Earth during the Neoproterozoic era in order to gain a deeper understanding of the rapid oxygenation that trigger the emergence of complex organisms. [9] [10]

Related Research Articles

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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: Selenium". CIAAW. 2013.
  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. ↑ The half-life of 79Se Archived September 27, 2011, at the Wayback Machine
  5. ↑ Jorg, Gerhard; Buhnemann, Rolf; Hollas, Simon; Kivel, Niko; Kossert, Karsten; Van Winckel, Stefaan; Gostomski, Christoph Lierse v. (2010). "Preparation of radiochemically pure 79Se and highly precise determination of its half-life". Applied Radiation and Isotopes. 68 (12): 2339–51. doi:10.1016/j.apradiso.2010.05.006. PMID   20627600.
  6. ↑ 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.
  7. 1 2 Shimizu, Y.; Kubo, T.; Sumikama, T.; Fukuda, N.; Takeda, H.; Suzuki, H.; Ahn, D. S.; Inabe, N.; Kusaka, K.; Ohtake, M.; Yanagisawa, Y.; Yoshida, K.; Ichikawa, Y.; Isobe, T.; Otsu, H.; Sato, H.; Sonoda, T.; Murai, D.; Iwasa, N.; Imai, N.; Hirayama, Y.; Jeong, S. C.; Kimura, S.; Miyatake, H.; Mukai, M.; Kim, D. G.; Kim, E.; Yagi, A. (8 April 2024). "Production of new neutron-rich isotopes near the N = 60 isotones Ge 92 and As 93 by in-flight fission of a 345 MeV/nucleon U 238 beam". Physical Review C. 109 (4). doi:10.1103/PhysRevC.109.044313.
  8. ↑ Shoemaker T; Vuong T; Glickman H; Kaifi S; Famulari G; Enger SA (2019). "Dosimetric Considerations for Ytterbium-169, Selenium-75, and Iridium-192 Radioisotopes in High-Dose-Rate Endorectal Brachytherapy". Int J Radiat Oncol Biol Phys. 105 (4): 875–883. doi:10.1016/j.ijrobp.2019.07.003. PMID   31330175. S2CID   198170324.
  9. ↑ Pogge von Strandmann, Philip A. E.; Stüeken, Eva E.; Elliott, Tim; Poulton, Simon W.; Dehler, Carol M.; Canfield, Don E.; Catling, David C. (2015-12-18). "Selenium isotope evidence for progressive oxidation of the Neoproterozoic biosphere". Nature Communications. 6 (1): 10157. doi: 10.1038/ncomms10157 . ISSN   2041-1723. PMC   4703861 . PMID   26679529.
  10. ↑ Stüeken, Eva E. "Selenium isotopes as a biogeochemical proxy in deep time" (PDF). core.ac.uk.
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