Plutonium - Pu General Information Discovery Plutonium was discovered by G.T. Seaborg, A.C. Wahl and J. W. Kennedy in 1940 in California, USA. Appearance Plutonium is a radioactive silvery metal that tarnishes in air to give an oxide coating with yellow tinge. Source The greatest source of plutonium - and one that produces 20,000 kilograms every year - is the irradiation of uranium in nuclear reactors. This produces the isotope 239Pu, with a half-life of 24400 years. Uses Plutonium was used in several of the first atomic bombs, and is still used for explosives. The complete detonation of a kilogram of plutonium produces an explosion equivalent to over 10000 tonnes of chemical explosive. Plutonium is also a key material in the development of nuclear power. It has been used as a compact energy source on space missions such as the Apollo lunar missions. Biological Role Plutonium has no known biological role. It is toxic due to its radioactivity. General Information Plutonium is attacked by oxygen, steam and acids, but not by alkalis. The metal is warm to the touch because of the energy given off in alpha decay, and a large piece of the metal can boil water. Plutonium forms compounds with oxygen, the halides, carbon, nitrogen and silicon.

	Physical Information
	Atomic Number		94
	Relative Atomic Mass (12C=12.000)		244 (radioactive)
	Melting Point/K		914
	Boiling Point/K		3505
	Density/kg m-3		19840 (298K)
	Ground State Electron Configuration		[Rn]5f67s2

	Key Isotopes
	nuclide	239Pu	242Pu	244Pu
	atomic mass	239.05	242.06	244.06
	natural abundance	0%	0%	0%
	half-life	24400 yrs	3.79x105 yrs	8.2x107 yrs

Other Information
Enthalpy of Fusion/kJ mol-1		2.8
Enthalpy of Vaporisation/kJ mol-1		343.5
Oxidation States
main	PuIV
others	PuII, PuIII, PuV, PuVI, PuVII
Covalent Bonds /kJ mol-1
not applicable

	Ionisation Energies/kJ mol-1
	M - M+	585
	M+ - M2+
	M2+ - M3+
	M3+ - M4+
	M4+ - M5+
	M5+ - M6+
	M6+ - M7+
	M7+ - M8+
	M8+ - M9+
	M9+ - M10+