Thorium: symbol Th, natural chemical element, solid, metal, radioactive, atomic number 90, actinoids family. Thorium can be used in nuclear power reactors - as precursor of 233U.
Lithium was isolated by William Thomas Brande and Sir Humphrey Davy through the electrolysis of lithium oxide (Li2O) in 1885.
Jons Jakob Berzelius (Sweden) in 1815.
Thorium fine powders are flamable and sometimes pyrophoric.