Li6

Lithium-6, symbol 6Li, is a stable isotope of the element lithium with a mass number of 6. Its nucleus contains three protons and three neutrons. In natural lithium, 6Li accounts for about 7.5% of the atoms, with the majority being 7Li. Like other lithium isotopes, 6Li is produced in small amounts during cosmic ray interactions and in stellar environments.

Its nuclear properties include a ground-state spin and parity of 1+ and a total binding energy of about 32 MeV (binding energy per nucleon around 5.3 MeV). 6Li is stable on laboratory timescales. A notable reaction is neutron capture: 6Li + n → 4He + 3H, releasing about 4.8 MeV. This reaction underpins several detector technologies and contributes to tritium production in fusion relevance.

Occurrence and production: 6Li occurs naturally in lithium-bearing minerals such as spodumene and petalite, and is separated from 7Li during isotopic enrichment. In the cosmos, 6Li is formed in trace amounts during Big Bang nucleosynthesis and is produced more abundantly by cosmic-ray spallation and in certain stellar environments. Its relative abundance helps in studies of lithium chemistry and cosmology.

Applications: 6Li is used in neutron detectors, often in Li-containing scintillators, glasses, or foils, due to its favorable neutron capture cross section. It also serves as a feedstock for breeding tritium in fusion reactors, via the 6Li(n,α)3H reaction. Enriched 6Li compounds are used in research and specialized industrial applications, while natural lithium supplies set overall abundances.