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.
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| Standard atomic weight Ar°(Se) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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List of isotopes
edit| 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 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 | 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 | 34 | 44 | 77.91730924(19) | Stable | 0 | 0.2369 (22) | |||||||||||||
| 79Se[n 10] | 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 | 34 | 46 | 79.9165218(10) | Observationally Stable[n 11] | 0 | 0.4980(36) | |||||||||||||
| 81Se | 34 | 47 | 80.9179930(10) | 18.45(12) min | β− | 81Br | 1/2− | ||||||||||||
| 81mSe | 103.00(6) keV | 57.28(2) min | IT (99.95%) | 81Se | 7/2 | ||||||||||||||
| β− (.051%) | 81Br | ||||||||||||||||||
| 82Se[n 12] | 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[7] | 34 | 62 | |||||||||||||||||
| 97Se[7] | 34 | 63 | |||||||||||||||||
| This table header & footer: | |||||||||||||||||||
- ^ mSe – Excited nuclear isomer.
- ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
- ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
- ^ Bold half-life – nearly stable, half-life longer than age of universe.
- ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
- ^
Modes of decay:
EC: Electron capture IT: Isomeric transition n: Neutron emission p: Proton emission - ^ Bold symbol as daughter – Daughter product is stable.
- ^ ( ) spin value – Indicates spin with weak assignment arguments.
- ^ Believed to decay by β β to 74Ge with a half-life over 2.3×1018 y.
- ^ Long-lived fission product
- ^ Believed to decay by β−β− to 80Kr
- ^ Primordial radionuclide
Use of radioisotopes
editThe 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]
References
edit- ^ 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.
- ^ "Standard Atomic Weights: Selenium". CIAAW. 2013.
- ^ 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.
- ^ The half-life of 79Se Archived September 27, 2011, at the Wayback Machine
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ Stüeken, Eva E. "Selenium isotopes as a biogeochemical proxy in deep time" (PDF). core.ac.uk.
- 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.