94
244.00
Pu
Plutonium
Identification
CAS Number: 7440-07-5
Discovery Year: 1940
Discoverer: G.T.Seaborg, J.W.Kennedy, E.M.McMillan, A.C.Wohl
Discovery Location: United States
Properties
Atomic Dimensions
Atomic Radius: 175 pm →
Atomic Radius (Rahm): 278 pm
Covalent Radius: 187 pm →Van der Waals Radius: 243.00000000000003 pm
Thermodynamics
Melting Point: 914 K →Boiling Point: 3505 K →Heat of Fusion: 2.8 kJ/mol →Heat of Vaporization: 343.5 kJ/mol →
Heat of Formation: 345 kJ/mol
Electronic Structure
Electron Config: [Rn] 5f6 7s2
Block: f
Period: 7 →Electronegativity: 1.3 →Oxidation States: +3, +4, +5, +6
Abundance & Geochemistry
Goldschmidt Class: synthetic
About
Dense silvery radioactive metallic transuranic element, belongs to the actinoids. Pu-244 is the most stable isotope with a half-life of 7.6*10^7 years. Thirteen isotopes are known. Pu-239 is the most important, it undergoes nuclear fission with slow neutrons and is hence important to nuclear weapons and reactors. Plutonium production is monitored down to the gram to prevent military misuse. First produced by Gleen T. Seaborg, Edwin M. McMillan, J.W. Kennedy and A.C. Wahl in 1940.
Isotopes
Pu-238 238 ☢ 87.7 a
Pu-239 239 ☢ 2.41e+4 a
Pu-240 240 ☢ 6.56e+3 a
Pu-241 241 ☢ 14.3 a
Pu-242 242 ☢ 3.75e+5 a
Pu-244 244 ☢ 8.00e+7 a