Isotopes of selenium (original) (raw)

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Isotopes of selenium (34Se)

Main isotopes[1] Decay Isotope abun­dance half-life (_t_1/2) mode pro­duct 72Se synth 8.40 d ε 72As 74Se 0.860% stable 75Se synth 119.78 d ε 75As 76Se 9.23% stable 77Se 7.60% stable 78Se 23.7% stable 79Se trace 3.27×105 y β− 79Br 80Se 49.8% stable 82Se 8.82% 8.76×1019 y β−β− 82Kr
Standard atomic weight _A_r°(Se)
78.971±0.008[2]78.971±0.008 (abridged)[3]
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Selenium 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 about 330,000 years,[4] and 82Se, which has the very long half-life of 8.76×1019 years as it decays via double beta decay to krypton-82 and for practical purposes can be considered to be stable. There are 23 other unstable isotopes that have been characterized, the longest-lived after 79Se being 75Se with its half-life 119.78 days, 72Se at 8.40 days, and 73Se at 7.15 hours. The others are all under an hour and most do not exceed 38 seconds.

| Nuclide[n 1] | Z | N | Isotopic mass (Da)[5][n 2][n 3] | Half-life[1][n 4][n 5] | Decay mode[1][n 6] | Daughter isotope[n 7] | Spin andparity[1][n 8][n 5] | Natural abundance (mole fraction) | | | ----------------------------------------------------------------------------------------------- | --------------------------------------------------- | ---------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- | | | Excitation energy | Normal proportion[1] | Range of variation | | | | | | | | | 63Se | 34 | 29 | 62.98191(54)# | 13.2(39) ms | β+, p (89%) | 62Ge | 3/2−# | | | | β+ (11%) | 63As | | | | | | | | | | 2p? (<0.5%) | 61Ge | | | | | | | | | | 64Se | 34 | 30 | 63.97117(54)# | 22.6(2) ms | β+? | 64As | 0+ | | | | β+, p? | 63Ge | | | | | | | | | | 65Se | 34 | 31 | 64.96455(32)# | 34.2(7) ms | β+, p (87%) | 64Ge | 3/2−# | | | | β+ (13%) | 65As | | | | | | | | | | 66Se | 34 | 32 | 65.95528(22)# | 54(4) ms | β+ | 66As | 0+ | | | | β+, p? | 65Ge | | | | | | | | | | 67Se | 34 | 33 | 66.949994(72) | 133(4) ms | β+ (99.5%) | 67As | 5/2−# | | | | β+, p (0.5%) | 66Ge | | | | | | | | | | 68Se | 34 | 34 | 67.94182524(53) | 35.5(7) s | β+ | 68As | 0+ | | | | 69Se | 34 | 35 | 68.9394148(16) | 27.4(2) s | β+ (99.95%) | 69As | 1/2− | | | | β+, p (.052%) | 68Ge | | | | | | | | | | 69m1Se | 38.85(22) keV | 2.0(2) μs | IT | 69Se | 5/2− | | | | | | 69m2Se | 574.0(4) keV | 955(16) ns | IT | 69Se | 9/2+ | | | | | | 70Se | 34 | 36 | 69.9335155(17) | 41.1(3) min | β+ | 70As | 0+ | | | | 71Se | 34 | 37 | 70.9322094(30) | 4.74(5) min | β+ | 71As | (5/2−) | | | | 71m1Se | 48.79(5) keV | 5.6(7) μs | IT | 71Se | (1/2−) | | | | | | 71m2Se | 260.48(10) keV | 19.0(5) μs | IT | 71Se | (9/2+) | | | | | | 72Se | 34 | 38 | 71.9271405(21) | 8.40(8) d | EC | 72As | 0+ | | | | 73Se | 34 | 39 | 72.9267549(80) | 7.15(9) h | β+ | 73As | 9/2+ | | | | 73mSe | 25.71(4) keV | 39.8(17) min | IT (72.6%) | 73Se | 3/2− | | | | | | β+ (27.4%) | 73As | | | | | | | | | | 74Se | 34 | 40 | 73.922475933(15) | **Observationally Stable**[n 9] | 0+ | 0.0086(3) | | | | | 75Se | 34 | 41 | 74.922522870(78) | 119.78(3) d | EC | **75As** | 5/2+ | | | | 76Se | 34 | 42 | 75.919213702(17) | **Stable** | 0+ | 0.0923(7) | | | | | 77Se[n 10] | 34 | 43 | 76.919914150(67) | **Stable** | 1/2− | 0.0760(7) | | | | | 77mSe | 161.9223(10) keV | 17.36(5) s | IT | **77Se** | 7/2+ | | | | | | 78Se[n 10] | 34 | 44 | 77.91730924(19) | **Stable** | 0+ | 0.2369 (22) | | | | | 79Se[n 11] | 34 | 45 | 78.91849925(24) | 3.27(28)×105 y | β− | **79Br** | 7/2+ | | | | 79mSe | 95.77(3) keV | 3.900(18) min | IT (99.94%) | 79Se | 1/2− | | | | | | β− (0.056%) | **79Br** | | | | | | | | | | 80Se[n 10] | 34 | 46 | 79.9165218(10) | **Observationally Stable**[n 12] | 0+ | 0.4980(36) | | | | | 81Se[n 10] | 34 | 47 | 80.9179930(10) | 18.45(12) min | β− | **81Br** | 1/2− | | | | 81mSe[n 10] | 103.00(6) keV | 57.28(2) min | IT (99.95%) | 81Se | 7/2+ | | | | | | β− (0.051%) | **81Br** | | | | | | | | | | 82Se[n 10][n 13] | 34 | 48 | 81.91669953(50) | **8.76(15)×1019 y** | β−β− | **82Kr** | 0+ | 0.0882(15) | | | 83Se | 34 | 49 | 82.9191186(33) | 22.25(4) min | β− | 83Br | 9/2+ | | | | 83mSe | 228.92(7) keV | 70.1(4) s | β− | 83Br | 1/2− | | | | | | 84Se | 34 | 50 | 83.9184668(21) | 3.26(10) min | β− | 84Br | 0+ | | | | 85Se | 34 | 51 | 84.9222608(28) | 32.9(3) s | β− | 85Br | (5/2)+ | | | | 86Se | 34 | 52 | 85.9243117(27) | 14.3(3) s | β− | 86Br | 0+ | | | | β−, n? | 85Br | | | | | | | | | | 87Se | 34 | 53 | 86.9286886(24) | 5.50(6) s | β− (99.50%) | 87Br | (3/2+) | | | | β−, n (0.60%) | 86Br | | | | | | | | | | 88Se | 34 | 54 | 87.9314175(36) | 1.53(6) s | β− (99.01%) | 88Br | 0+ | | | | β−, n (0.99%) | 87Br | | | | | | | | | | 89Se | 34 | 55 | 88.9366691(40) | 430(50) ms | β− (92.2%) | 89Br | 5/2+# | | | | β−, n (7.8%) | 88Br | | | | | | | | | | 90Se | 34 | 56 | 89.94010(35) | 210(80) ms | β− | 90Br | 0+ | | | | β−, n? | 89Br | | | | | | | | | | 91Se | 34 | 57 | 90.94570(47) | 270(50) ms | β− (79%) | 91Br | 1/2+# | | | | β−, n (21%) | 90Br | | | | | | | | | | β−, 2n? | 89Br | | | | | | | | | | 92Se | 34 | 58 | 91.94984(43)# | 90# ms [>300 ns] | β−? | 92Br | 0+ | | | | β−, n? | 91Br | | | | | | | | | | β−, 2n? | 90Br | | | | | | | | | | 92mSe | 3072(2) keV | 15.7(7) μs | IT | 92Se | (9−) | | | | | | 93Se | 34 | 59 | 92.95614(43)# | 130# ms [>300 ns] | β−? | 93Br | 1/2+# | | | | β−, n? | 92Br | | | | | | | | | | β−, 2n? | 91Br | | | | | | | | | | 93mSe | 678.2(7) keV | 420(100) ns | IT | 93Se | | | | | | | 94Se | 34 | 60 | 93.96049(54)# | 50# ms [>300 ns] | β−? | 94Br | 0+ | | | | β−, n? | 93Br | | | | | | | | | | β−, 2n? | 92Br | | | | | | | | | | 94mSe | 2430.0(6) keV | 680(50) ns | IT | 94Se | (7−) | | | | | | 95Se | 34 | 61 | 94.96730(54)# | 70# ms [>400 ns] | β−? | 95Br | 3/2+# | | | | β−, n? | 94Br | | | | | | | | | | β−, 2n? | 93Br | | | | | | | | | | 96Se[6] | 34 | 62 | | | | | | | | | 97Se[6] | 34 | 63 | | | | | | | | | This table header & footer: view | | | | | | | | | |

  1. ^ mSe – Excited nuclear isomer.
  2. ^ ( ) – Uncertainty (1_σ_) 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. ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  6. ^ Modes of decay:
  7. ^ Bold symbol as daughter – Daughter product is stable.
  8. ^ ( ) spin value – Indicates spin with weak assignment arguments.
  9. ^ Theoretically capable of β+β+ decay to 74Ge; half-life is above 2.3×1018 y.
  10. ^ a b c d e f Fission product
  11. ^ Long-lived fission product
  12. ^ Theoretically capable of β−β− decay to 80Kr
  13. ^ Primordial radionuclide

Use of radioisotopes

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The isotope selenium-75 has radiopharmaceutical uses. For example, it is used in high-dose-rate endorectal brachytherapy, as an alternative to iridium-192.[7]

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.[8][9]

Daughter products other than selenium

  1. ^ a b c d e 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. ^ 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.
  5. ^ 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.
  6. ^ a b 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.
  7. ^ 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.
  8. ^ 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.
  9. ^ Stüeken, Eva E. "Selenium isotopes as a biogeochemical proxy in deep time" (PDF). core.ac.uk.