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Properties and data of the isotope 23Na.



Sodium-23 isotope

Sodium-23 is a natural and stable isotope of the chemical element sodium, which, in addition to the element-specific 11 protons, has 12 neutrons in the atomic nucleus, resulting in the mass number 23. 23Na is the only stable nuclide of sodium; It is therefore a monoisotopic element.

See also: list of Sodium isotopes.


General data

Name of the isotope:Sodium-23; Na-23Symbol:23Na or 2311NaMass number A:23 (= number of nucleons)Atomic number Z:11 (= number of protons)Neutrons N:12Isotopic mass:22.98976928(2) u (atomic weight of Sodium-23)Nuclide mass:22.9837349 u (calculated nuclear mass without electrons)Mass excess:-9.52985 MeVMass defect:0.200285064 u (per nucleus)Nuclear binding energy:186.56433541 MeV (per nucleus)
8.11149284 MeV (average binding energy per nucleon)
Separation energy:SN = 12.41978(13) MeV (first neutron)
SP = 8.794109(18) MeV (first proton)
Half-life:stableSpin and parity:
(nuclear angular momentum)
3/2+Magnetic dipole moment:μ(μN) = +2.21750(3)Charge radius:2.9936(21) femtometer fmMirror nucleus:Magnesium-23Year of discovery:1921


Parent Nuclides

Direct parent isotopes are: 23Mg, 23Ne.



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


Atomic Mass maQuantityHalf-lifeSpin
Isotopic mixture
22.98976928 u100 %
Isotope 23Na22.98976928(2) u100 %stable3/2+
Isotope 24Na23.990963012(18) u
14.956(3) h4+
Isotope 22Na21.99443755(14) u
2.6018(22) a3+



There are various applications in technology and medicine that are based on the nuclear or nuclear magnetic properties of the nuclide sodium-23, especially as a nuclear magnetic resonance-active isotope (see below) in NMR Spectroscopy.

Among the various analytical techniques, Na-23 nuclear magnetic resonance (23Na-NMR) is a powerful tool for studying the chemical interactions and dynamic behavior of the omnivalent sodium ions. Relaxation plays a particularly important role here, a process in nuclear magnetic resonance spectroscopy and magnetic resonance imaging (MRI), which describes the temporal fall back (relaxation time) of the nuclear spin magnetization to the equilibrium state and - depending on the atomic nucleus - is based on different relaxation mechanisms [5].

In practice, the appropriate techniques open up a wide variety of investigation options, such as the solution behavior of sodium ions [1] or solid-state NMR analysis of the NIB electrode materials of Na-ion batteries [3] .

In biochemistry, 23Na NMR spectroscopy is used to research metabolic processes in which Na ions are often involved, as well as to elucidate the structure and function of biomolecules such as for example, proteins and DNA [4].

Medicine finally uses sodium-23 in the form of 23Na magnetic resonance imaging (23Na-MRI ) as a biomarker and for the diagnosis or prognosis of various diseases and energy metabolism as well as for imaging [2].


NMR data

Nuclear magnetic properties of the NMR active Nuclide 23Na

Isotope:23Na-NMRQuantity:100 %Spin:3/2+Nuclearmagnetic moment
+2.21750(3)Gyromagnetic ratio γ:7.0801 · 107 rad T-1 s-1Nuclear g-factor:gl = 1.4783333333333Quadrupole moment Q:+0.104(1) barn (100 fm2)Line width parameter (factor):l = 144.21 fm4Resonance frequency:v0 = 11.2688 at 1 TRelative Sensitivity:0.09270 (H0 = const.)
1.3234 (v0 = const.)
[related to 1H = 1.000]


Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 12) and isobaric (same nucleon number A = 23) with Sodium-23. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.


OZIsotone N = 12Isobar A = 23


External data and identifiers

Adopted Levels, Gammas:NuDat 23Na


Literature and References

[1] - E. G. Bloor, R. G. Kidd:
Solvation of sodium ions studied by 23Na nuclear magnetic resonance.
In: Canadian Journal of Chemistry, 46, 22, (1968), DOI 10.1139/v68-569.

[2] - Linda Osei Poku, M. Phil, Yongna Cheng, Kai Wang, Xilin Sun:
23Na-MRI as a Noninvasive Biomarker for Cancer Diagnosis and Prognosis.
In: JMRI, 53, 4, 995-1014, (2020), DOI 10.1002/jmri.27147.

[3] - Dr. Kazuma Gotoh:
23Na Solid-State NMR Analyses for Na-Ion Batteries and Materials.
In: Batteries & Supercaps, 4, 8, 1267-1278, (2021), DOI 10.1002/batt.202000295.

[4] - Binhan Yu, Karina G. Bien, Channing C. Pletka, Junji Iwahara:
Dynamics of Cations around DNA and Protein as Revealed by 23Na Diffusion NMR Spectroscopy.
In: Analytical Chemistry, 94, 4, 2444-2452, (2022), DOI 10.1021/acs.analchem.1c04197.

[5] - Yifan Song, Yu Yin, Qinlong Chen, Alessandro Marchetti, Xueqian Kong:
23Na relaxometry: An overview of theory and applications.
In: Magnetic Resonance Letters, 3, 2, 150-174, (2023), DOI 10.1016/j.mrl.2023.04.001.


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Last update: 2023-11-06

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