Plutonium

Plutonium, chemical element, symbol Pu; for physical constants see Periodic Table. Discovered by Glenn Seaborg and co-workers in 1940. It was produced by bombarding uranium with deuterons in a cyclotron. It exists in trace quantities in nature in uranium ores. It is produced in large quantities in nuclear reactors from uranium-238. Plutonium is prepared by the reduction of its trifluoride with alkaline-earth metals. It is a silvery, radioactive, toxic metal, a member of the actinide series. Plutonium is used as an explosive in nuclear weapons and as nuclear reactor fuel. Plutonium-238 is used as a thermoelectric generator and heat source. In handling plutonium and its compounds, care must be taken to ensure that a critical mass is not formed, especially in liquid solution. Plutonium is the most important of the transuranium elements.