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Magnesium-25

Properties and data of the isotope 25Mg.


Contents

 

Magnesium-25 isotope

Magnesium-25 is a stable isotope of the chemical element magnesium, which has 13 neutrons in its atomic nucleus in addition to the element-specific 12 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 25. 25Mg is one of the three isotopes that make up the earth's natural magnesium deposits (see below).

In 1920, the physicist Arthur Jeffrey Dempster described the isotopic composition of magnesium for the first time. For his experiments, he used an apparatus for positive ray analysis; the cylindrical anode contained the magnesium and was irradiated with electrons [1].

See also: list of Magnesium isotopes.

 

General data

Name of the isotope:Magnesium-25; Mg-25Symbol:25Mg or 2512MgMass number A:25 (= number of nucleons)Atomic number Z:12 (= number of protons)Neutrons N:13Isotopic mass:24.9858370(3) u (atomic weight of Magnesium-25)Nuclide mass:24.9792541 u (calculated nuclear mass without electrons)Mass excess:-13.19275 MeVMass defect:0.220707292 u (per nucleus)Nuclear binding energy:205.58751825 MeV (per nucleus)
8.22350073 MeV (average binding energy per nucleon)
Separation energy:SN = 7.33053(5) MeV (first neutron)
SP = 12.06385(5) MeV (first proton)
Half-life:stableSpin and parity:
(nuclear angular momentum)
5/2+Magnetic dipole moment:μ(μN) = -0.85533(3)Charge radius:3.0284(22) femtometer fmMirror nucleus:Aluminium-25Year of discovery:1920

 

Parent Nuclides

Direct parent isotopes are: 25Al, 25Na.

 

Occurrence

Comparison of the natural Magnesium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

 

Atomic Mass maQuantityHalf-lifeSpin
Magnesium
Isotopic mixture
24.305 u100 %
Isotope 24Mg23.98504170(9) u78.965(49) %
[78.88 - 79.05 %]
stable0+
Isotope 25Mg24.9858370(3) u10.011 %
[9.988 - 10.034 %]
stable5/2+
Isotope 26Mg25.9825930(2) u11.024 %
[10.96 - 11.09 %]
stable0+

 

NMR data

Nuclear magnetic properties of the NMR active Nuclide 25Mg

Isotope:25Mg-NMRQuantity:10.011 % [9.988 - 10.034 %]Spin:5/2+Nuclearmagnetic moment
μ/μN:
-0.85533(3)Gyromagnetic ratio γ:- 1.639 · 107 rad T-1 s-1Nuclear g-factor:gl = -0.342132Quadrupole moment Q:+ 0.1994(20) barn (100 fm2)Resonance frequency:v0 = 2.6083 at 1 TFrequency ratio:Ξ(25Mg) = 6.121635 %Relative Sensitivity:0.002698 (H0 = const.)
0.7147 (v0 = const.)
[related to 1H = 1.000]
Reference compound:
(conditions)
Solution of magnesium chloride MgCl2 (11 M) in deuterium oxide D2O.

Magnesium-25 has the only NMR-active atomic nucleus of the three natural magnesium isotopes. The nuclide is quadrupolar with a spin of 5/2 and has only a low sensitivity. The NMR signal width is narrow in symmetrical environments and increases with the asymmetry of the environment, such as in Grignard compounds. The chemical shift of inorganic magnesium is strongly solvent-dependent. Overall, 25NMR spectroscopy is a rarely used special application.

 

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 13) and isobaric (same nucleon number A = 25) with Magnesium-25. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

 

ZIsotone N = 13Isobar A = 25
518B
619C
720N25N
821O25O
922F25F
1023Ne25Ne
1124Na25Na
1225Mg25Mg
1326Al25Al
1427Si25Si
1528P25P
1629S
1730Cl
1831Ar
1932K

 

External data and identifiers

Adopted Levels, Gammas:NuDat 25Mg

 

Literature and References

[1] - A. J. Dempster:
Positive Ray Analysis of Lithium and Magnesium.
In: Physical Review, 18, 415, (1921), DOI 10.1103/PhysRev.18.415.

[2] - Jair C.C. Freitas, Mark E. Smith:
Recent Advances in Solid-State 25Mg NMR Spectroscopy.
In: Annual Reports on NMR Spectroscopy, 75, (2012), DOI 10.1016/B978-0-12-397018-3.00002-8.

 


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Last update: 2024-11-06


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