Isotopes of magnesium

Magnesium (Mg) naturally occurs in three stable isotopes, ²⁴Mg, ²⁵Mg, and ²⁶Mg. 19 radioisotopes 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

A chart showing the abundances of the naturally-occurring isotopes of magnesium.

Table

nuclide symbol	proton	neutron	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+
²⁰Mg	12	8	20.018863(29)	90.8(24) ms	β⁺, p (3%)	¹⁹Ne	0+
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+
³⁰Mg	12	18	29.990434(9)	335(17) ms	β⁻, n (.06%)	²⁹Al	0+
³¹Mg	12	19	30.996546(13)	230(20) ms	β⁻ (98.3%)	³¹Al	3/2+
³¹Mg	12	19	30.996546(13)	230(20) ms	β⁻, n (1.7%)	³⁰Al	3/2+
³²Mg	12	20	31.998975(19)	86(5) ms	β⁻ (97.6%)	³²Al	0+
³²Mg	12	20	31.998975(19)	86(5) ms	β⁻, n (2.4%)	³¹Al	0+
³³Mg	12	21	33.005254(21)	90.5(16) ms	β⁻ (83%)	³³Al	7/2-#
³³Mg	12	21	33.005254(21)	90.5(16) ms	β⁻, n (17%)	³²Al	7/2-#
³⁴Mg	12	22	34.00946(25)	20(10) ms	β⁻ (>99.9%)	³⁴Al	0+
³⁴Mg	12	22	34.00946(25)	20(10) ms	β⁻, n (<.1%)	³³Al	0+
³⁵Mg	12	23	35.01734(43)#	70(40) ms	β⁻, n (52%)	³⁴Al	(7/2-)#
³⁵Mg	12	23	35.01734(43)#	70(40) ms	β⁻ (48%)	³⁵Al	(7/2-)#
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-#
³⁷Mg	12	25	37.03140(97)#	40# ms [>260 ns]	β⁻, n	³⁶Al	7/2-#
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

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". 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 and 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 and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". 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

Magnesium isotopes data from The Berkeley Laboratory Isotopes Project's

↑ http://www.nucleonica.net/unc.aspx

Isotopes of sodium	Isotopes of magnesium	Isotopes of aluminium
Table of nuclides

Isotopes of the chemical elements
1 H																	2 He
3 Li	4 Be											5 B	6 C	7 N	8 O	9 F	10 Ne
11 Na	12 Mg											13 Al	14 Si	15 P	16 S	17 Cl	18 Ar
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
		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
Table of nuclides Categories: Isotopes Tables of nuclides Metastable isotopes Isotopes by element