Magnesium-23

Properties and data of the isotope ²³Mg.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Magnesium-23 is a radioisotope of the chemical element magnesium, which has 11 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 23. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²³Mg is exclusively for academic purposes and experimental research.

According to a report from 1939, the isotope was first observed during irradiation of sodium chloride with 6 MeV protons [1]; magnesium-23 was formed from the sodium-23 present in NaCl according to the charge exchange reaction ²³Na(p,n)²³Mg.

General data

Name of the isotope:Magnesium-23; Mg-23Symbol:²³Mg or 2312MgMass number A:23 (= number of nucleons)Atomic number Z:12 (= number of protons)Neutrons N:11Isotopic mass:22.99412377(3) u (atomic weight of Magnesium-23)Nuclide mass:22.9875409 u (calculated nuclear mass without electrons)Mass excess:-5.47367 MeVMass defect:0.19509069 u (per nucleus)Nuclear binding energy:181.72580719 MeV (per nucleus)
7.90112205 MeV (average binding energy per nucleon)Separation energy:S_N = 13.14501(16) MeV (first neutron)
S_P = 7.58125(14) MeV (first proton)Half-life:11.3046(45) sDecay constant λ:0.061315498165344 s^-1Specific activity α:1.67841166749 × 10⁺²¹ Bq g^-1
45362477499.865 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μ_N) = -0.5363(3)Quadrupole moment Q:11.4(3) barn (100 fm²)Nuclear g-factor:g_l = -0.35753333333333Charge radius:0 femtometer fmMirror nucleus:Sodium-23Year of discovery:1939

Radioactive Decay

Half-life T_½ = 11.3046(45) s respectively 1.13046 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC β⁺	²³Na	100 %	4.05618(3) MeV

Parent Nuclides

Direct parent isotopes are: ²⁴Si, ²³Al.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 11) and isobaric (same nucleon number A = 23) with Magnesium-23. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 11	Isobar A = 23
4	¹⁵Be
5	¹⁶B
6	¹⁷C
7	¹⁸N	²³N
8	¹⁹O	²³O
9	²⁰F	²³F
10	²¹Ne	²³Ne
11	²²Na	²³Na
12	²³Mg	²³Mg
13	²⁴Al	²³Al
14	²⁵Si	²³Si
15	²⁶P
16	²⁷S
17	²⁸Cl