Magnesium (Mg) naturally occurs in three stable isotopes, 24Mg, 25Mg, and 26Mg. There are 19 radioisotopes that have been discovered, ranging from 19Mg to 40Mg. The longest-lived radioisotope is 28Mg with a half-life of 20.915 hours. The lighter isotopes mostly decay to isotopes of sodium while the heavier isotopes decay to isotopes of aluminium. The shortest-lived is 39Mg with a half-life shorter than 180 nanoseconds, or possibly 40Mg, with a half-life longer than 170 nanoseconds (the half-life of 19Mg is unknown).
Standard atomic mass: 24.3050(6) u
Table[edit]
nuclide symbol |
Z(p) | N(n) | isotopic mass (u) |
half-life | decay mode(s)[1] | daughter isotope(s)[n 1] |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
---|---|---|---|---|---|---|---|---|---|
19Mg | 12 | 7 | 19.03547(27) | 1/2−# | |||||
20Mg | 12 | 8 | 20.018863(29) | 90.8(24) ms | β+ (97%) | 20Na | 0+ | ||
β+, p (3%) | 19Ne | ||||||||
21Mg | 12 | 9 | 21.011713(18) | 122(2) ms | β+ (66.9%) | 21Na | (5/2,3/2)+ | ||
β+, p (32.6%) | 20Ne | ||||||||
β+, α (0.5%) | 17F | ||||||||
22Mg | 12 | 10 | 21.9995738(14) | 3.8755(12) s | β+ | 22Na | 0+ | ||
23Mg | 12 | 11 | 22.9941237(14) | 11.317(11) s | β+ | 23Na | 3/2+ | ||
24Mg | 12 | 12 | 23.985041700(14) | Stable | 0+ | 0.7899(4) | 0.78958–0.79017 | ||
25Mg | 12 | 13 | 24.98583692(3) | Stable | 5/2+ | 0.1000(1) | 0.09996–0.10012 | ||
26Mg[n 2] | 12 | 14 | 25.982592929(30) | Stable | 0+ | 0.1101(3) | 0.10987–0.11030 | ||
27Mg | 12 | 15 | 26.98434059(5) | 9.458(12) min | β− | 27Al | 1/2+ | ||
28Mg | 12 | 16 | 27.9838768(22) | 20.915(9) h | β− | 28Al | 0+ | ||
29Mg | 12 | 17 | 28.988600(15) | 1.30(12) s | β− | 29Al | 3/2+ | ||
30Mg | 12 | 18 | 29.990434(9) | 335(17) ms | β− (99.94%) | 30Al | 0+ | ||
β−, n (.06%) | 29Al | ||||||||
31Mg | 12 | 19 | 30.996546(13) | 230(20) ms | β− (98.3%) | 31Al | 3/2+ | ||
β−, n (1.7%) | 30Al | ||||||||
32Mg | 12 | 20 | 31.998975(19) | 86(5) ms | β− (97.6%) | 32Al | 0+ | ||
β−, n (2.4%) | 31Al | ||||||||
33Mg | 12 | 21 | 33.005254(21) | 90.5(16) ms | β− (83%) | 33Al | 7/2−# | ||
β−, n (17%) | 32Al | ||||||||
34Mg | 12 | 22 | 34.00946(25) | 20(10) ms | β− (>99.9%) | 34Al | 0+ | ||
β−, n (<.1%) | 33Al | ||||||||
35Mg | 12 | 23 | 35.01734(43)# | 70(40) ms | β−, n (52%) | 34Al | (7/2−)# | ||
β− (48%) | 35Al | ||||||||
36Mg | 12 | 24 | 36.02300(54)# | 3.9(13) ms | β− | 36Al | 0+ | ||
37Mg | 12 | 25 | 37.03140(97)# | 40# ms [>260 ns] | β− | 37Al | 7/2−# | ||
β−, n | 36Al | ||||||||
38Mg | 12 | 26 | 38.03757(54)# | 1# ms [>260 ns] | 0+ | ||||
39Mg | 12 | 27 | 39.04677(55)# | <260 ns | 7/2−# | ||||
40Mg | 12 | 28 | 40.05393(97)# | 1# ms | 0+ |
- ^ Bold for stable isotopes
- ^ Used in radiodating events early in the Solar System's history
References[edit]
- Isotope masses from:
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
- Isotopic compositions and standard atomic masses from:
- J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
- Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.
External links[edit]
- ^ "Universal Nuclide Chart". nucleonica. (registration required (help)).
Isotopes of sodium | Isotopes of magnesium | Isotopes of aluminium |
Table of nuclides |
Isotopes of the chemical elements | |||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 H |
2 He |
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3 Li |
4 Be |
5 B |
6 C |
7 N |
8 O |
9 F |
10 Ne |
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11 Na |
12 Mg |
13 Al |
14 Si |
15 P |
16 S |
17 Cl |
18 Ar |
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19 K |
20 Ca |
21 Sc |
22 Ti |
23 V |
24 Cr |
25 Mn |
26 Fe |
27 Co |
28 Ni |
29 Cu |
30 Zn |
31 Ga |
32 Ge |
33 As |
34 Se |
35 Br |
36 Kr |
37 Rb |
38 Sr |
39 Y |
40 Zr |
41 Nb |
42 Mo |
43 Tc |
44 Ru |
45 Rh |
46 Pd |
47 Ag |
48 Cd |
49 In |
50 Sn |
51 Sb |
52 Te |
53 I |
54 Xe |
55 Cs |
56 Ba |
![]() |
72 Hf |
73 Ta |
74 W |
75 Re |
76 Os |
77 Ir |
78 Pt |
79 Au |
80 Hg |
81 Tl |
82 Pb |
83 Bi |
84 Po |
85 At |
86 Rn |
87 Fr |
88 Ra |
![]() |
104 Rf |
105 Db |
106 Sg |
107 Bh |
108 Hs |
109 Mt |
110 Ds |
111 Rg |
112 Cn |
113 Uut |
114 Fl |
115 Uup |
116 Lv |
117 Uus |
118 Uuo |
![]() |
57 La |
58 Ce |
59 Pr |
60 Nd |
61 Pm |
62 Sm |
63 Eu |
64 Gd |
65 Tb |
66 Dy |
67 Ho |
68 Er |
69 Tm |
70 Yb |
71 Lu |
||
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89 Ac |
90 Th |
91 Pa |
92 U |
93 Np |
94 Pu |
95 Am |
96 Cm |
97 Bk |
98 Cf |
99 Es |
100 Fm |
101 Md |
102 No |
103 Lr |
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