Plutonium • Actinide Rare Earth
Symbol: Pu
Date of discovery: 1940
Name origin: planet Pluto
Appearance: silver-white
Discoverer: G.T. Seaborg
Obtained from: uranium ores, man-made
Melting point: 913 K
Boiling point: 3503 K
Density[kg/m3]: 19816
Molar volume: 12.29 × 10-6 m3/mol
Protons/Electrons: 94
Neutrons: 150
Shell structure: 2,8,18,32,24,8,2
Electron configuration: [Rn]5f67s2
Oxidation state: 6,5,4,3
Crystal Structure: monoclinic
Named after the planet Pluto, plutonium was the second transuranium element of the actinide series discovered. Its appearance is silver-white, though it tarnishes to yellow when slightly oxidized. The isotope 239Pu has a half-life over 20,000 years; one kilogram produces over 20 million kilowatt hours of heat energy. Applications of plutonium include use as an explosive ingredient in nuclear weapons and as a key material in the development of nuclear power. Because of the energy given off by alpha decay, a large piece of plutonium is warm to the touch. Although plutonium occurs naturally in trace amounts, most existing plutonium has been created from fissile activity, particularly in nuclear power reactors.
