Despite the name it is not actually Lithium
A bluish gas.
Found in some gas giants, for reasons unknown, this gas is used by some to create shield generators, or enhance power plant production due to is high electrical conductivity.
The gas is poisonous to most organics, typically putting the victim in a stupor before they pass out into a coma. Some have used this substance at low doses to pacify populations, making it a controlled substance to most of the galaxy.