Periodic Table


Atomic number: 94
Atomic weight: 244
Symbol: Pu
Group number: (actinide)
Electronic configuration: [Rn].5f6.7s2


Plutonium was the second transuranium element of the actinide series to be discovered. By far of greatest importance is the isotope 239Pu, which has a half-life of more than 20000 years. One kilogram is equivalent to about 22 million kilowatt hours of heat energy. The complete detonation of a kilogram of plutonium produces an explosion equal to about 20000 tons of chemical explosive. The various nuclear applications of plutonium are well known. The isotope 233Pu was used in the American Apollo lunar missions to power seismic and other equipment on the lunar surface. Plutonium contamination is an emotive environmental problem.

General information

Discoveror: Glenn T. Seaborg , J. W. Kennedy, E. M. McMillan, A. C. Wahl
Date discovered: 1940
Discovered at: USA
Meaning of name: Named after "the planet Pluto"

Physical data

Standard state: solid at 298 K
Colour: silvery white
Density of solid at ambient temperature/kg m-3: 19816
Molar volume/cm3: 12.29

Radii /pm

Atomic: no data
Covalent (single bond):
Pauling radius for the ion [Pu]-: no data

Valence shell orbital radius maxima (Rmax)
orbital s p d f
radius230.8no datano data49.7


Both values are quoted on the Pauling scale.

Pauling: 1.28
Allred Rochow: 1.22

Crystal Structure

structure: monoclinic

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.


Temperatures (/K)

melting point: 912.5
boiling point: 3503

Enthalpies /kJ mol-1

fusion: no data
vaporization: 333

single bond enthalpies:
Pu-F Pu-Cl Pu-Br Pu-I Pu-Pu
no data no data no data 310 no data

Ionization enthalpies /kJ mol-1

Number Enthalpy


This section gives some data for naturally occurring isotopes.
Nominal mass Accurate mass % natural abundance

Further Information

Copyright 1997 Mark Winter
Department of Chemistry at the University of Sheffield, Sheffield S3 7HF, England.

The current version of this document is at http://www.shef.ac.uk/~chem/web-elements-I/Pu.html