نظائر المغنسيوم

قالب:Infobox magnesium isotopes

المغنسيوم (Mg)
الكتلة الذرية القياسية: 24.3050(6) u

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-unbound 19 Mg with a half-life of 5(3) picoseconds, though the half-life of similarly unbound 18 Mg has not been measured.

A precise measurement of the neutron-rich 40Mg in 2019 showed the unexpected difference in its nuclear structure, compared to the lighter neighboring isotopes.[1][2]

The abundances of the naturally occurring isotopes of magnesium.

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List of isotopes

Nuclide[3]
 Z N Isotopic mass (Da)[4]
[n 1] 		Half-life
[n 2] 		Decay
mode
[n 3] 		Daughter
isotope
[n 4] 		Spin and
parity
[n 5][n 2] 		التوافر الطبيعي (mole fraction)
Normal proportion Range of variation
18 Mg[5] 12 6 2p 16 Ne 0+
19 Mg 12 7 19.034180(60) 5(3) ps 2p 17 Ne 1/2−#
20 Mg 12 8 20.0187631(20) 90.4(5) ms β+ (69.7(1.2)%) 20 Na 0+
β+p (30.3(1.2)%) 19 Ne
21 Mg 12 9 21.0117058(8) 120.0(4) ms β+ (79.8(2.1)%) 21 Na 5/2+
β+p (20.1(2.1)%) 20 Ne
β+α (0.116(18)%) 17 F
β+pα (0.016(3)%) 16 O
22 Mg 12 10 21.99957060(17) 3.8745(7) s β+ 22 Na 0+
23 Mg 12 11 22.99412377(3) 11.3039(32) s β+ 23 Na 3/2+
24 Mg 12 12 23.985041689(14) Stable 0+ [0.7888, 0.7905]
25 Mg 12 13 24.98583697(5) Stable 5/2+ [0.09988, 0.10034]
26 Mg[n 6] 12 14 25.98259297(3) Stable 0+ [0.1096, 0.1109]
27 Mg 12 15 26.98434065(5) 9.435(27) min β− 27 Al 1/2+
28 Mg 12 16 27.98387543(28) 20.915(9) h β− 28 Al 0+
29 Mg 12 17 28.9886072(4) 1.30(12) s β− 29 Al 3/2+
30 Mg 12 18 29.9904655(14) 317(4) ms β− (> 99.94%) 30 Al 0+
β−n (< 0.06%) 29 Al
31 Mg 12 19 30.996648(3) 270(2) ms β− (93.8(1.9)%) 31 Al 1/2+
β−n (6.2(1.9)%) 30 Al
32 Mg 12 20 31.999110(4) 80.4(4) ms β− (94.5(5)%) 32 Al 0+
β−n (5.5(5)%) 31 Al
33 Mg 12 21 33.0053279(29) 92.0(1.2) ms β− (86(2)%) 33 Al 3/2−
β−n (14(2)%) 32 Al
β−2n ?[n 7] 31 Al ?
34 Mg 12 22 34.008935(7) 44.9(4) ms β− (> 78.9(7.0)%) 34 Al 0+
β−n (21(7)%) 33 Al
β−2n (< 0.1%) 32 Al
35 Mg 12 23 35.01679(29) 11.3(6) ms β−n (52(46)%) 34 Al (3/2−, 5/2−)
β− (48(46)%) 35 Al
β−2n ?[n 7] 33 Al ?
36 Mg 12 24 36.02188(74) 3.9(1.3) ms β− (52(12)%) 36 Al 0+
β−n (48(12)%) 35 Al
β−2n ?[n 7] 34 Al ?
37 Mg 12 25 37.03029(75) 8(4) ms β− ?[n 7] 37 Al ? (3/2−)
β−n ?[n 7] 36 Al ?
β−2n ?[n 7] 35 Al ?
38 Mg 12 26 38.03658(54)# 3.1(4 (stat), 2 (sys)) ms[6] β−n (81%) 37 Al 0+
β− (9%) 38 Al
β−2n (9%) 36 Al
40 Mg 12 28 40.05319(54)# 1# ms [> 170 ns] β− ?[n 7] 40 Al ? 0+
β−n ?[n 7] 39 Al ?
β−2n ?[n 7] 38 Al ?
This table header & footer:  view 
  1. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
  2. ^ أ ب # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
  3. ^ أنماط الاضمحلال:
    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. ^ أ ب ت ث ج ح خ د ذ Decay mode shown is energetically allowed, but has not been experimentally observed to occur in this nuclide.


وصلات خارجية

المراجع

  1. ^ glennroberts (2019-02-07). "New Measurements of Exotic Magnesium Suggest Surprising Shape-Shift". Berkeley Lab News Center (in الإنجليزية الأمريكية). Retrieved 2023-09-10.
  2. ^ "NP A Change in Structure for a S... | U.S. DOE Office of Science(SC)". science.osti.gov (in الإنجليزية الأمريكية). 2019-08-01. Retrieved 2023-09-10.
  3. ^ Half-life, decay mode, nuclear spin, and isotopic composition is sourced in:
    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.
  4. ^ 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.
  5. ^ 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.
  6. ^ 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.
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