Notable Isotopes 
6Li [3 neutrons]
Abundance: 7.5%
Stable with 3 neutrons
| Lithium-6 is valued as a source material for tritium (an isotope of hydrogen) production and as a neutron absorber in nuclear fusion. |
7Li [4 neutrons]Abundance: 92.5%
Stable with 4 neutrons
| 7Li is one of the primordial elements or, more properly, primordial isotopes, produced in Big Bang nucleosynthesis (a small amount of 6Li is also produced in stars). |