Isotopes of aluminium

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Isotopes of aluminium  (13Al)
Main isotopes [1] Decay
Isotope abun­dance half-life (t1/2) mode pro­duct
26Al trace 7.17×105 y β+ 26Mg
27Al100% stable
Standard atomic weight Ar°(Al)

Aluminium or aluminum (13Al) has one stable isotope, 27Al, comprising all natural aluminium. The radioactive 26Al, with half-life 717,000 years, occurs in traces from cosmic-ray spallation of argon in the atmosphere.

Contents

Other than 26Al, there are 22 known synthetic radioisotopes from 20Al to 43Al, and 4 known metastable states; all have half-lives under 7 minutes, most under a second.

26Al is an extinct radionuclide and has received attention as such, being used in the study of meteorites. Its terrestrial occurrence has also 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. [4]

List of isotopes


Nuclide
[n 1] 		Z N Isotopic mass (Da) [5]
[n 2] [n 3] 		Half-life [1]
Decay
mode [1]
[n 4] 		Daughter
isotope
[n 5] 		Spin and
parity [1]
[n 6] [n 7] 		Isotopic
abundance
Excitation energy [n 7]
20Al [6] 13720.04326(13)>1.1 zsp19Mg(1−)
21Al [7] 13821.0278(13)>1.1 zsp20Mg(5/2+)
22Al13922.01942310(32) [8] 91.1(5) msβ+, p (55%)21Na(4)+
β+ (44%)22Mg
β+, 2p (1.10%)20Ne
β+, α (0.038%)18Ne
23Al131023.00724435(37)446(6) msβ+ (98.78%)23Mg5/2+
β+, p (1.22%)22Na
24Al131123.99994760(24)2.053(4) sβ+ (99.96%)24Mg4+
β+, α (0.035%)20Ne
β+, p (0.0016%)23Na
24mAl425.8(1) keV130(3) ms IT (82.5%)24Al1+
β+ (17.5%)24Mg
β+, α (0.028%)20Ne
25Al131224.990428308(69)7.1666(23) sβ+25Mg5/2+
26Al [n 8] 131325.986891876(71)7.17(24)×105 yβ+ (85%)26Mg5+Trace [n 9]
EC (15%) [9]
26mAl228.306(13) keV6.3460(5) sβ+26Mg0+
27Al131426.981538408(50)Stable5/2+1.0000
28Al131527.981910009(52)2.245(5) minβ−28Si3+
29Al131628.98045316(37)6.56(6) minβ−29Si5/2+
30Al131729.9829692(21)3.62(6) sβ−30Si3+
31Al131830.9839498(24)644(25) msβ− (>98.4%)31Si5/2+
β−, n (<1.6%)30Si
32Al131931.9880843(77)32.6(5) msβ− (99.3%)32Si1+
β−, n (0.7%)31Si
32mAl956.6(5) keV200(20) nsIT32Al(4+)
33Al132032.9908777(75)41.46(9) msβ− (91.5%)33Si5/2+
β−, n (8.5%)32Si
34Al132133.9967819(23)53.73(13) msβ− (74%)34Si4−
β−, n (26%)33Si
34mAl46.4(17) keV22.1(2) msβ− (89%)34Si1+
β−, n (11%)33Si
35Al132234.9997598(79)38.16(21) msβ− (64.2%)35Si(5/2+,3/2+)
β−, n (35.8%)34Si
36Al132336.00639(16)90(40) msβ− (>69%)36Si
β−, n (<31%)35Si
37Al132437.01053(19)11.4(3) msβ−, n (52%)36Si5/2+#
β− (<47%)37Si
β−, 2n (>1%)35Si
38Al132538.01768(16)#9.0(7) msβ−, n (84%)37Si0−#
β− (16%)38Si
39Al132639.02307(32)#7.6(16) msβ−, n (97%)38Si5/2+#
β− (3%)39Si
40Al132740.03094(32)#5.7(3 (stat), 2 (sys)) ms [10] β−, n (64%)39Si
β−, 2n (20%)38Si
β− (16%)40Si
41Al132841.03713(43)#3.5(8 (stat), 4 (sys)) ms [10] β−, n (86%)40Si5/2+#
β−, 2n (11%)39Si
β− (3%)41Si
42Al132942.04508(54)#3# ms
[>170 ns]
43Al133043.05182(64)#4# ms
[>170 ns]		β−?43Si5/2+#
This table header & footer:
  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. 1 2 # – 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

The decay level scheme for Al and Al to Mg. Al-26v2.png
The decay level scheme for Al and Al to Mg.

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. [13]

See also

Daughter products other than aluminum

References

  1. 1 2 3 4 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: Aluminium". CIAAW. 2017.
  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. ↑ Dickin, A.P. (2005). "In situ Cosmogenic Isotopes". Radiogenic Isotope Geology. Cambridge University Press. ISBN   978-0-521-53017-0. Archived from the original on 6 December 2008. Retrieved 16 July 2008.
  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. ↑ Kostyleva, D.; Xu, X.-D.; Mukha, I.; et al. (2025-07-10). "Isospin Symmetry Breaking Disclosed in the Decay of Three-Proton Emitter 20Al". Physical Review Letters. 135 (2). doi: 10.1103/hkmy-yfdk . ISSN   0031-9007.
  7. ↑ Kostyleva, D.; Xu, X.-D.; Mukha, I.; et al. (2024-09-03). "Observation and spectroscopy of the proton-unbound nucleus 21Al". Physical Review C. 110 (3). arXiv: 2406.04771 . doi:10.1103/PhysRevC.110.L031301. ISSN   2469-9985.
  8. ↑ Campbell, S. E.; Bollen, G.; Brown, B. A.; Dockery, A.; Ireland, C. M.; Minamisono, K.; Puentes, D.; Rickey, B. J.; Ringle, R.; Yandow, I. T.; Fossez, K.; Ortiz-Cortes, A.; Schwarz, S.; Sumithrarachchi, C. S.; Villari, A. C. C. (9 April 2024). "Precision Mass Measurement of the Proton Dripline Halo Candidate Al 22". Physical Review Letters. 132 (15). doi:10.1103/PhysRevLett.132.152501.
  9. ↑ Mougeot, X. (2019). "Towards high-precision calculation of electron capture decays". Applied Radiation and Isotopes. 154 (108884). doi: 10.1016/j.apradiso.2019.108884 .
  10. 1 2 Crawford, H. L.; Tripathi, V.; Allmond, J. M.; et al. (2022). "Crossing N = 28 toward the neutron drip line: first measurement of half-lives at FRIB". Physical Review Letters. 129 (212501): 212501. Bibcode:2022PhRvL.129u2501C. doi: 10.1103/PhysRevLett.129.212501 . PMID   36461950. S2CID   253600995.{{cite journal}}: CS1 maint: article number as page number (link)
  11. ↑ "Physics 6805 Topics in Nuclear Physics". Ohio State University. Archived from the original on 2 September 2021. Retrieved 12 June 2019.
  12. ↑ Diehl, R (13 Dec 2005). "26Al in the inner Galaxy" (PDF). Astronomy & Astrophysics. 449 (3): 1025–1031. doi: 10.1051/0004-6361:20054301 . Retrieved 12 June 2019.
  13. ↑ R. T. Dodd (1986). Thunderstones and Shooting Stars . Harvard University Press. pp.  89–90. ISBN   978-0-674-89137-1.
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