Isotopes of aluminium

Short description: Nuclides with atomic number of 13 but with different mass numbers

Main isotopes of Chemistry:aluminium (13Al) | Iso­tope | Decay

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| abun­dance | half-life (t1/2) | mode | pro­duct
26Al  | trace | 7.17×105 y  | β+ (85%)  | 26Mg
ε (15%)  | 26Mg
γ | –
27Al  | 100%  | stable
Standard atomic weight Ar, standard(Al)|

* 26.9815385(7)[1]

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Aluminium or aluminum (13Al) has 22 known isotopes from 22Al to 43Al and 4 known isomers. Only 27Al (stable isotope) and 26Al (radioactive isotope, t1/2 = 7.2×105 y) occur naturally, however 27Al comprises nearly all natural aluminium. Other than 26Al, all radioisotopes have half-lives under 7 minutes, most under a second. The standard atomic weight is 26.9815385(7). 26Al is produced from argon in the atmosphere by spallation caused by cosmic-ray protons. Aluminium isotopes have found practical application in dating marine sediments, manganese nodules, glacial ice, quartz in rock exposures, and meteorites. The ratio of 26Al to 10Be has been used to study the role of sediment transport, deposition, and storage, as well as burial times, and erosion, on 105 to 106 year time scales.[citation needed] 26Al has also played a significant role in the study of meteorites.

## Contents

* 1 List of isotopes
* 2 Aluminium-26
* 3 References
* 4 External links

## List of isotopes

Nuclide[2]
[n 1] | Z | N | Isotopic mass (u)[3]
[n 2][n 3] | Half-life
| Decay
mode
[n 4] | Daughter
isotope
[n 5] | Spin and
parity
[n 6][n 7] | Physics:Natural abundance (mole fraction)

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Excitation energy[n 7] | Normal proportion  | Range of variation
22Al  | 13  | 9  | 22.01954(43)#  | 91.1(5) ms  | β+, p (55%)  | 21Na  | (4)+  |  |
β+ (43.862%)  | 22Mg
β+, 2p (1.1%)  | 20Ne
β+, α (0.038%)  | 18Ne
23Al  | 13  | 10  | 23.0072444(4)  | 470(30) ms  | β+ (99.54%)  | 23Mg  | 5/2+  |  |
β+, p (0.46%)  | 22Na
24Al  | 13  | 11  | 23.99994754(25)  | 2.053(4) s  | β+ (99.9634%)  | 24Mg | 4+  |  |
β+, α (.035%)  | 20Ne
β+, p (.0016%)  | 23Na
24mAl  | 425.8(1) keV  | 130(3) ms  | IT (82.5%)  | 24Al  | 1+  |  |
β+ (17.5%)  | 24Mg
β+, α (.028%)  | 20Ne
25Al  | 13  | 12  | 24.99042831(7)  | 7.183(12) s  | β+ | 25Mg | 5/2+  |  |
26Al[n 8] | 13  | 13  | 25.98689186(7)  | 7.17(24)×105 y  | β+ (85%)  | 26Mg | 5+  | Trace[n 9] |
ε (15%)[4]
26mAl  | 228.306(13) keV  | 6.3460(8) s  | β+ | 26Mg | 0+  |  |
27Al  | 13  | 14  | 26.98153841(5)  | Stable | 5/2+  | 1.0000  |
28Al  | 13  | 15  | 27.98191009(8)  | 2.245(5) min  | β− | 28Si | 3+  |  |
29Al  | 13  | 16  | 28.9804532(4)  | 6.56(6) min  | β− | 29Si | 5/2+  |  |
30Al  | 13  | 17  | 29.982968(3)  | 3.62(6) s  | β− | 30Si | 3+  |  |
31Al  | 13  | 18  | 30.9839498(24)  | 644(25) ms  | β− (98.4%)  | 31Si  | 5/2(+)  |  |
β−, n (1.6%)  | 30Si
32Al  | 13  | 19  | 31.988084(8)  | 33.0(2) ms  | β− (99.3%)  | 32Si  | 1+  |  |
β−, n (.7%)  | 31Si
32mAl  | 955.7(4) keV  | 200(20) ns  | IT  | 32Al  | (4+)  |  |
33Al  | 13  | 20  | 32.990878(8)  | 41.7(2) ms  | β− (91.5%)  | 33Si  | 5/2+  |  |
β−, n (8.5%)  | 32Si
34Al  | 13  | 21  | 33.996779(3)  | 56.3(5) ms  | β− (74%)  | 34Si  | (4−)  |  |
β−, n (26%)  | 33Si
34mAl  | 550(100)# keV  | 26(1) ms  | β− (70%)  | 34Si  | (1+)  |  |
β−, n (30%)  | 33Si
35Al  | 13  | 22  | 34.999760(8)  | 37.2(8) ms  | β− (62%)  | 35Si  | 5/2+#  |  |
β−, n (38%)  | 34Si
36Al  | 13  | 23  | 36.00639(16)  | 90(40) ms  | β− (70%)  | 36Si  |  |  |
β−, n (30%)  | 35Si
37Al  | 13  | 24  | 37.01053(19)  | 11.5(4) ms  | β− (71%)  | 37Si  | 5/2+#  |  |
β−, n (29%)  | 36Si
38Al  | 13  | 25  | 38.0174(4)  | 9.0(7) ms  | β− | 38Si  |  |  |
39Al  | 13  | 26  | 39.02217(43)#  | 7.6(16) ms  | β−, n (90%)  | 38Si  | 5/2+#  |  |
β− (10%)  | 39Si
40Al  | 13  | 27  | 40.02962(43)#  | 5.7(3 (stat), 2 (sys)) ms[5] | β−, n (64%)  | 39Si  |  |  |
β−, 2n (20%)  | 38Si
β− (16%)  | 40Si
41Al  | 13  | 28  | 41.03588(54)#  | 3.5(8 (stat), 4 (sys)) ms[5] | β−, n (86%)  | 40Si  | 5/2+#  |  |
β−, 2n (11%)  | 39Si
β− (3%)  | 41Si
42Al  | 13  | 29  | 42.04305(64)#  | 1# ms [>170 ns]  | β− | 42Si  |  |  |
43Al  | 13  | 30  | 43.05048(86)#  | 1# ms [>170 ns]  | β− | 43Si  |  |  |

1. ↑ mAl - 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. ↑ Modes of decay:  IT: | Isomeric transition

|

5. ↑ Bold symbol as daughter - Daughter product is stable.
6. ↑ ( ) spin value - Indicates spin with weak assignment arguments.
7. ↑ 7.0 7.1 # - Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
8. ↑ Used in radiodating events early in the Solar System's history and meteorites
9. ↑ cosmogenic

## Aluminium-26

Main article: Physics:Aluminium-26

The decay level scheme for 26Al and 26mAl to 26Mg.[4][6]

Cosmogenic aluminium-26 was first described in studies of the Moon and meteorites. Meteorite fragments, after departure from their parent bodies, are exposed to intense cosmic-ray bombardment during their travel through space, causing substantial 26Al production. After falling to Earth, atmospheric shielding protects the meteorite fragments from further 26Al production, and its decay can then be used to determine the meteorite's terrestrial age. Meteorite research has also shown that 26Al was relatively abundant at the time of formation of our planetary system. Most meteoriticists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago.[7]

## References

1. ↑ Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry 88 (3): 265–91. doi:10.1515/pac-2015-0305.
2. ↑ Half-life, decay mode, nuclear spin, and isotopic composition is sourced in:
Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties". Chinese Physics C 41 (3): 030001. doi:10.1088/1674-1137/41/3/030001. Bibcode: 2017ChPhC..41c0001A. https://www-nds.iaea.org/amdc/ame2016/NUBASE2016.pdf.
3. ↑ Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references". Chinese Physics C 41 (3): 030003-1—030003-442. doi:10.1088/1674-1137/41/3/030003. http://nuclearmasses.org/resources_folder/Wang_2017_Chinese_Phys_C_41_030003.pdf.
4. ↑ 4.0 4.1 "Physics 6805 Topics in Nuclear Physics". Ohio State University. https://www.asc.ohio-state.edu/physics/ntg/6805/figures/al26scheme.jpg.
5. ↑ 5.0 5.1 Crawford, H. L.Expression error: Unrecognized word "et". (2022). "Crossing N = 28 toward the neutron drip line: first measurement of half-lives at FRIB". Physical Review Letters 129 (212501): 212501. doi:10.1103/PhysRevLett.129.212501. PMID 36461950. Bibcode: 2022PhRvL.129u2501C.
6. ↑ Diehl, R (13 Dec 2005). "26Al in the inner Galaxy". Astronomy & Astrophysics 449 (3): 1025–1031. doi:10.1051/0004-6361:20054301. http://www2011.mpe.mpg.de/gamma/science/lines/26Al/Al26_SPI_A&A2005_astro-ph.pdf. Retrieved 12 June 2019.
7. ↑ R. T. Dodd (1986). Thunderstones and Shooting Stars. Harvard University Press. pp. 89–90. ISBN 978-0-674-89137-1. https://archive.org/details/thunderstonessho00dodd_673.

## External links

* Aluminum isotopes data from The Berkeley Laboratory Isotopes Project's

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