Nuclides with atomic number of 12 but with different mass numbers
Magnesium (12Mg) naturally occurs in three stable isotopes: 24 Mg, 25 Mg, and 26 Mg. There are 19 radioisotopes that have been discovered, ranging from 18 Mg to 40 Mg (with the exception of 39 Mg). The longest-lived radioisotope is 28 Mg with a half-life of 20.915(9) h. The lighter isotopes mostly decay to isotopes of sodium while the heavier isotopes decay to isotopes of aluminium. The shortest-lived is proton-unbound18 Mg with a half-life of 4.0(3.4) zeptoseconds.
A precise measurement of the neutron-rich 40Mg in 2019 showed the unexpected difference in its nuclear structure, compared to the lighter neighboring isotopes.[4][5]
The abundances of the naturally occurring isotopes of magnesium.
List of isotopes
^( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
^ a b# – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
^Modes of decay:
^Bold symbol as daughter – Daughter product is stable.
^( ) spin value – Indicates spin with weak assignment arguments.
^Used in radiodating events early in the Solar System's history
^ a b c d e f g h iDecay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.
External links
Magnesium isotopes data from The Berkeley Laboratory Isotopes Project's
References
^ a b c d eKondev, 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.
^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.
^glennroberts (2019-02-07). "New Measurements of Exotic Magnesium Suggest Surprising Shape-Shift". Berkeley Lab News Center. Retrieved 2023-09-10.
^"NP A Change in Structure for a S... | U.S. DOE Office of Science(SC)". science.osti.gov. 2019-08-01. Retrieved 2023-09-10.
^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.
^Jin, Y.; et al. (2021). "First observation of the four-proton unbound nucleus 18Mg". Physical Review Letters. 127 (262502): 262502. doi:10.1103/PhysRevLett.127.262502. OSTI 1837749. PMID 35029460. S2CID 245434485.
^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.