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.
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 ma | Quantity | Half-life | Spin | |
|---|---|---|---|---|
| Lithium Isotopic mixture | 6.94 u | 100 % | ||
| Isotope 6Li | 6.015122887(9) u | 4.85 % [1.9 - 7.8 %] | stable | 1+ |
| Isotope 7Li | 7.01600344(3) u | 95.15 % [92.2 - 98.1 %] | stable | 3/2- |
Nuclear magnetic properties of the NMR active Nuclide 7Li
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.
| Z | Isotone N = 4 | Isobar A = 7 |
|---|---|---|
| 1 | 5H | 7H |
| 2 | 6He | 7He |
| 3 | 7Li | 7Li |
| 4 | 8Be | 7Be |
| 5 | 9B | 7B |
| 6 | 10C | |
| 7 | 11N | |
| 8 | 12O | |
| 9 | 13F |
[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.
Last update: 2023-12-02
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