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Properties and data of the isotope 7Li.



Lithium-7 isotope

Lithium-7 is a stable isotope of the chemical element Lithium, which, in addition to the element-specific 3 protons, has 4 neutrons in the atomic nucleus, resulting in the mass number 7.

See also: list of Lithium isotopes.


General data

Name of the isotope:Lithium-7; Li-7Symbol:7Li or 73LiMass number A:7 (= number of nucleons)Atomic number Z:3 (= number of protons)Neutrons N:4Isotopic mass:7.01600344(3) u (atomic weight of Lithium-7)Nuclide mass:7.0143577 u (calculated nuclear mass without electrons)Mass excess:14.90711 MeVMass defect:0.042131319999999 u (per nucleus)Nuclear binding energy:39.24507179 MeV (per nucleus)
5.60643883 MeV (average binding energy per nucleon)
Separation energy:SN = 7.251093(4) MeV (first neutron)
SP = 9.97396(5) MeV (first proton)
Half-life:stableSpin and parity:
(nuclear angular momentum)
3/2-Isobaric spin: 1/2Magnetic dipole moment:μ(μN) = +3.256407(12)Charge radius:2.444(42) femtometer fmMirror nucleus:Beryllium-7Year of discovery:1921


Parent Nuclides

Direct parent isotopes are: 11Be, 7Be.



Lithium-7 is a primordial nuclide that was largely created during the Big Bang; a smaller percentage comes from the spallation of other nuclides under the influence of cosmic rays. Earth's Li deposits are made up of two isotopes: Li-7, with an average of 95.15%, makes up the much larger proportion (Lithium-6: 4.85%).

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


Atomic Mass maQuantityHalf-lifeSpin
Isotopic mixture
6.94 u100 %
Isotope 6Li6.015122887(9) u4.85 %
[1.9 - 7.8 %]
Isotope 7Li7.01600344(3) u95.15 %
[92.2 - 98.1 %]


NMR data

Nuclear magnetic properties of the NMR active Nuclide 7Li

Isotope:7Li-NMRQuantity:95.15 % [92.2 - 98.1 %]Spin:3/2-Nuclearmagnetic moment
+3.256407(12)Gyromagnetic ratio γ:10.3976 · 107 rad T-1 s-1Nuclear g-factor:gl = 2.170938Quadrupole moment Q:-0.0400(3) barn (100 fm2)Line width parameter (factor):l = 21.33 fm4Resonance frequency:v0 = 16.5483 at 1 TFrequency ratio:Ξ(7Li) = 38.863797 %Relative Sensitivity:0.29356 (H0 = const.)
1.9434 (v0 = const.)
[related to 1H = 1.000]
Reference compound:
Solution of lithium chloride (9.7 m LiCl) in deuterium oxide (D2O).

The NMR spectroscopy of lithium is based on two different quadrupolar nuclei, of which 7Li (95.15%) is much more common in natural samples than the nuclide lithium-6, which is also suitable for NMR. The chemical shift range of both nuclides is quite small at around 30 ppm. Due to the highly symmetrical structure of the Li+ cation, aqueous lithium salt solutions are best suited for precise NMR measurements.

7Li NMR spectroscopy is not often used. More recently, however, the method has been used to investigate the electrochemical processes in lithium-containing batteries.


Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 4) and isobaric (same nucleon number A = 7) with Lithium-7. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.


OZIsotone N = 4Isobar A = 7


External data and identifiers

CAS:13982-05-3InChI Key:WHXSMMKQMYFTQS-IGMARMGPSA-NSMILES:[7Li]PubChem:ID 11564465Adopted Levels, Gammas:NuDat 7Li


Literature and References

[1] - Włodzimierz Makulski:
The Radiofrequency NMR Spectra of Lithium Salts in Water; Reevaluation of Nuclear Magnetic Moments for 6Li and 7Li Nuclei.
In: Magnetochemistry, 4(1), 9, (2018), DOI 10.3390/magnetochemistry4010009.

[2] - Annica I. Freytag et al.:
In Situ Magic-Angle Spinning 7Li NMR Analysis of a Full Electrochemical Lithium-Ion Battery Using a Jelly Roll Cell Design.
In: Journal of the American Chemical Society, 141, 35, 13758–13761, (2019), DOI 10.1021/jacs.9b06885.

[3] - Verena Küpers et al.:
In situ 7Li-NMR analysis of lithium metal surface deposits with varying electrolyte compositions and concentrations.
In: PCCP, (2019), DOI 10.1039/C9CP05334D.

[4] - Leonid B. Krivdin:
Recent advances in the liquid-phase 6,7Li nuclear magnetic resonance.
In: MRC, (2022), DOI 10.1002/mrc.5323.


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Last update: 2023-12-02

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