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Plutonium(IV) oxide



Plutonium (IV) Oxide
General
Systematic name Plutonium(IV) oxide
Other names Plutonium dioxide
Molecular formula O2Pu
Molar mass 276.063 g/mol
Appearance Yellow-brown crystalline
solid.
CAS number [12059-95-9]
Properties
Density and phase 11.5 g/cm³, solid
Solubility in water insoluble
Melting point 2400 °C (2673.15 K)
Boiling point 2800 °C (3073.15 K)
Structure
Coordination
geometry
8-coordinate Pu
Crystal structure Cubic
Hazards
MSDS External MSDS
Main hazards Radioactive, highly toxic
NFPA 704
1
4
2
OX
estimated 
DOT Classes
Flash point Non-flammable
R/S statement R: ?
S: ?
RTECS number na
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Related compounds
Related compounds UO2, CaF2
Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
Infobox disclaimer and references

Plutonium(IV) oxide is the chemical compound with the formula PuO2. This high melting point, yellow-brown, solid is a principal compound of plutonium.

Additional recommended knowledge

Contents

Structure

PuO2 crystallizes in the fluorite motif, with the Pu4+ centers organized in a face-centered cubic array. Oxide ions occupying tetrahedral holes. PuO2 owes utility as a nuclear fuel to the fact that vacancies in the octahedral holes allows room for fissile products. In nuclear fission, one atom of plutonium splits into two. The vacancy of the octahedral holes provides room for the new product and allows the PuO2 monolith to retain its structural integrity.

Synthesis

Plutonium metal spontaneously oxidizes to PuO2 in an atmosphere of oxygen. Plutonium dioxide is mainly produced by calcination of plutonium(IV) oxalate, Pu(C2O4)2.6H2O, at 300 °C. Plutonium oxalate is obtained during the reprocessing of nuclear fuel.

Applications

PuO2 is used in mixed oxide (MOX) fuels for nuclear reactors. Plutonium-238 dioxide is used as fuel for several deep-space spacecraft such as the 'New Horizons' Pluto probe. The isotope decays by emitting α-particles which then generate heat (see Radioisotope thermoelectric generator). There has been some safety concerns, as an accidental orbital earth re-entry may lead to the break-up and/or burn-up of the spacecraft, resulting in the dispersal of the plutonium either, over a large tract of the planetary surface, or within the upper atmosphere.

Safety

As with all plutonium compounds, it is subject to control under the Nuclear Non-Proliferation Treaty. Due to the radioactivity of plutonium, all of its compounds, PuO2 included, are warm to the touch, although touching the material may result in serious injury.

See also

  • International Atomic Energy Agency

Sources

  • Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4. 
  • Space Radioisotope Power Systems Safety
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Plutonium(IV)_oxide". A list of authors is available in Wikipedia.
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