Isotopes of magnesium
Appearance
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Standard atomic weight Ar°(Mg) | ||||||||||||||||||||||||||
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Magnesium (12Mg) naturally occurs in three stable isotopes, 24Mg, 25Mg, and 26Mg. There are 19 radioisotopes that have been discovered, ranging from 19Mg to 40Mg. The longest-lived radioisotope is 28Mg with a half-life of 20.915 hours. The lighter isotopes mostly decay to isotopes of sodium while the heavier isotopes decay to isotopes of aluminium. The shortest-lived is 39Mg with a half-life shorter than 180 nanoseconds, or possibly 40Mg, with a half-life longer than 170 nanoseconds (the half-life of 19Mg is unknown).
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Magnesium_chart.png/220px-Magnesium_chart.png)
List of isotopes
nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | decay mode(s)[4] | daughter isotope(s)[n 1] |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
---|---|---|---|---|---|---|---|---|---|
19Mg | 12 | 7 | 19.03547(27) | 4×10−12 s | 2p | 17Ne | 1/2−# | ||
20Mg | 12 | 8 | 20.018863(29) | 90.8(24) ms | β+ (97%) | 20Na | 0+ | ||
β+, p (3%) | 19Ne | ||||||||
21Mg | 12 | 9 | 21.011713(18) | 122(2) ms | β+ (66.9%) | 21Na | (5/2,3/2)+ | ||
β+, p (32.6%) | 20Ne | ||||||||
β+, α (0.5%) | 17F | ||||||||
22Mg | 12 | 10 | 21.9995738(14) | 3.8755(12) s | β+ | 22Na | 0+ | ||
23Mg | 12 | 11 | 22.9941237(14) | 11.317(11) s | β+ | 23Na | 3/2+ | ||
24Mg | 12 | 12 | 23.985041700(14) | Stable | 0+ | 0.7899(4) | 0.78958–0.79017 | ||
25Mg | 12 | 13 | 24.98583692(3) | Stable | 5/2+ | 0.1000(1) | 0.09996–0.10012 | ||
26Mg[n 2] | 12 | 14 | 25.982592929(30) | Stable | 0+ | 0.1101(3) | 0.10987–0.11030 | ||
27Mg | 12 | 15 | 26.98434059(5) | 9.458(12) min | β− | 27Al | 1/2+ | ||
28Mg | 12 | 16 | 27.9838768(22) | 20.915(9) h | β− | 28Al | 0+ | ||
29Mg | 12 | 17 | 28.988600(15) | 1.30(12) s | β− | 29Al | 3/2+ | ||
30Mg | 12 | 18 | 29.990434(9) | 335(17) ms | β− (99.94%) | 30Al | 0+ | ||
β−, n (.06%) | 29Al | ||||||||
31Mg | 12 | 19 | 30.996546(13) | 230(20) ms | β− (98.3%) | 31Al | 3/2+ | ||
β−, n (1.7%) | 30Al | ||||||||
32Mg | 12 | 20 | 31.998975(19) | 86(5) ms | β− (97.6%) | 32Al | 0+ | ||
β−, n (2.4%) | 31Al | ||||||||
33Mg | 12 | 21 | 33.005254(21) | 90.5(16) ms | β− (83%) | 33Al | 7/2−# | ||
β−, n (17%) | 32Al | ||||||||
34Mg | 12 | 22 | 34.00946(25) | 20(10) ms | β− (>99.9%) | 34Al | 0+ | ||
β−, n (<.1%) | 33Al | ||||||||
35Mg | 12 | 23 | 35.01734(43)# | 70(40) ms | β−, n (52%) | 34Al | (7/2−)# | ||
β− (48%) | 35Al | ||||||||
36Mg | 12 | 24 | 36.02300(54)# | 3.9(13) ms | β− | 36Al | 0+ | ||
37Mg | 12 | 25 | 37.03140(97)# | 40# ms [>260 ns] | β− | 37Al | 7/2−# | ||
β−, n | 36Al | ||||||||
38Mg | 12 | 26 | 38.03757(54)# | 1# ms [>260 ns] | 0+ | ||||
39Mg | 12 | 27 | 39.04677(55)# | <260 ns | 7/2−# | ||||
40Mg | 12 | 28 | 40.05393(97)# | 1# ms | 0+ |
- ^ Bold for stable isotopes
- ^ Used in radiodating events early in the Solar System's history
References
- Isotope masses from:
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
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- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
- Isotopic compositions and standard atomic masses from:
- J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
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- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
{{cite journal}}
: Unknown parameter|deadurl=
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suggested) (help) - National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
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(help) - N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide (ed.). CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.
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- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23.
External links
- ^ 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: Magnesium". CIAAW. 2011.
- ^ 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.
- ^ "Universal Nuclide Chart". nucleonica.
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