Plutonium - 94Pu: historical information
Plutonium was synthesized by Seaborg, McMillan, Kennedy and Wahl in 1940 by deuteron bombardment of uranium in a cyclotron (a device used to accelerate atomic particles) at Berkeley, California, USA. Plutonium was the second transuranium element of the actinide series to be discovered. In 1808 plutonium was suggested as a name for element 56 but Sir Humphrey Davy's original name of barium for element 56 still stands.