Physics:Isotopes of magnesium

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Short description: Nuclides with atomic number of 12 but with different mass numbers
Main isotopes of Chemistry:magnesium (12Mg)
Iso­tope Decay
abun­dance half-life (t1/2) mode pro­duct
24Mg 79.0% stable
25Mg 10.0% stable
26Mg 11.0% stable
Standard atomic weight Ar, standard(Mg)
  • [24.304, 24.307][1]
  • Conventional: 24.305
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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 18Mg to 40Mg (with the exception of 39Mg). The longest-lived radioisotope is 28Mg 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-unbound 18Mg 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.[2][3]

The abundances of the naturally occurring isotopes of magnesium.

List of isotopes

Nuclide
 Z N Isotopic mass (u)
[n 1] 		Half-life
[n 2] 		Decay
mode
[n 3] 		Daughter
isotope
[n 4] 		Spin and
parity
[n 5][n 2] 		Physics:Natural abundance (mole fraction)
Normal proportion Range of variation
18Mg[4] 12 6 4.0(3.4) zs 2p 16Ne 0+
19Mg 12 7 19.034180(60) 5(3) ps 2p 17Ne 1/2−#
20Mg 12 8 20.0187631(20) 90.4(5) ms β+ (69.7(1.2)%) 20Na 0+
β+p (30.3(1.2)%) 19Ne
21Mg 12 9 21.0117058(8) 120.0(4) ms β+ (79.8(2.1)%) 21Na 5/2+
β+p (20.1(2.1)%) 20Ne
β+α (0.116(18)%) 17F
β+pα (0.016(3)%) 16O
22Mg 12 10 21.99957060(17) 3.8745(7) s β+ 22Na 0+
23Mg 12 11 22.99412377(3) 11.3039(32) s β+ 23Na 3/2+
24Mg 12 12 23.985041689(14) Stable 0+ [0.7888, 0.7905]
25Mg 12 13 24.98583697(5) Stable 5/2+ [0.09988, 0.10034]
26Mg[n 6] 12 14 25.98259297(3) Stable 0+ [0.1096, 0.1109]
27Mg 12 15 26.98434065(5) 9.435(27) min β− 27Al 1/2+
28Mg 12 16 27.98387543(28) 20.915(9) h β− 28Al 0+
29Mg 12 17 28.9886072(4) 1.30(12) s β− 29Al 3/2+
30Mg 12 18 29.9904655(14) 317(4) ms β− (> 99.94%) 30Al 0+
β−n (< 0.06%) 29Al
31Mg 12 19 30.996648(3) 270(2) ms β− (93.8(1.9)%) 31Al 1/2+
β−n (6.2(1.9)%) 30Al
32Mg 12 20 31.999110(4) 80.4(4) ms β− (94.5(5)%) 32Al 0+
β−n (5.5(5)%) 31Al
33Mg 12 21 33.0053279(29) 92.0(1.2) ms β− (86(2)%) 33Al 3/2−
β−n (14(2)%) 32Al
β−2n ?[n 7] 31Al ?
34Mg 12 22 34.008935(7) 44.9(4) ms β− (> 78.9(7.0)%) 34Al 0+
β−n (21(7)%) 33Al
β−2n (< 0.1%) 32Al
35Mg 12 23 35.01679(29) 11.3(6) ms β−n (52(46)%) 34Al (3/2−, 5/2−)
β− (48(46)%) 35Al
β−2n ?[n 7] 33Al ?
36Mg 12 24 36.02188(74) 3.9(1.3) ms β− (52(12)%) 36Al 0+
β−n (48(12)%) 35Al
β−2n ?[n 7] 34Al ?
37Mg 12 25 37.03029(75) 8(4) ms β− ?[n 7] 37Al ? (3/2−)
β−n ?[n 7] 36Al ?
β−2n ?[n 7] 35Al ?
38Mg 12 26 38.03658(54)# 3.1(4 (stat), 2 (sys)) ms[5] β−n (81%) 37Al 0+
β− (9%) 38Al
β−2n (9%) 36Al
40Mg 12 28 40.05319(54)# 1# ms [> 170 ns] β− ?[n 7] 40Al ? 0+
β−n ?[n 7] 39Al ?
β−2n ?[n 7] 38Al ?
  1. ↑ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  2. ↑ 2.0 2.1 # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  3. ↑ Modes of decay:
    n: Neutron emission
    p: Proton emission
  4. ↑ Bold symbol as daughter – Daughter product is stable.
  5. ↑ ( ) spin value – Indicates spin with weak assignment arguments.
  6. ↑ Used in radiodating events early in the Solar System's history
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.

External links

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. ↑ glennroberts (2019-02-07). "New Measurements of Exotic Magnesium Suggest Surprising Shape-Shift" (in en-US). https://newscenter.lbl.gov/2019/02/07/new-measurements-exotic-magnesium-suggest-surprising-shape-shift/. 
  3. ↑ "NP A Change in Structure for a S... | U.S. DOE Office of Science(SC)" (in en-US). 2019-08-01. https://science.osti.gov/np/Highlights/2019/NP-2019-08-a. 
  4. ↑ Jin, Y. (2021). "First observation of the four-proton unbound nucleus 18Mg". Physical Review Letters 127 (262502): 262502. doi:10.1103/PhysRevLett.127.262502. PMID 35029460. 
  5. ↑ 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. 



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