Plutonium dioxide
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| Plutonium dioxide | |
|---|---|
  |
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| General | |
| Systematic name | Plutonium(IV) oxide |
| Other names | Plutonium dioxide |
| Molecular formula | PuO2 |
| 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 | ? g/100 ml (? °C) |
| Melting point | 2400°C (2673.15 K) |
| Boiling point | 2800°C (3073.15 K) |
| Structure | |
| Molecular shape | Linear |
| Coordination geometry |
? |
| Crystal structure | Cubic |
| Dipole moment | ? D |
| 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 | ? |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | ? |
| Other cations | ? |
| Related ? | ? |
| Related compounds | ? |
| 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 a high melting point, yellow-brown, crystalline solid at standard temperature and pressure. Due to the radioactivity of plutonium, PuO2 is warm to the touch, although touching the material may result in serious injury.
Contents |
[edit] Structure
PuO2 crystallizes with plutonium ions in a face-centered cubic array. The oxygen atoms create a cubic cell by occupying the tetrahedral holes of the plutonium matrix. The vacancy of the octahedral holes in the crystal lattice allows space for fissile products, affording PuO2 its utility as a nuclear fuel. During nuclear fission, one atom of plutonium splits into two. The vacancy of the octahedral holes provides room for the new product and allows PuO2 to retain its structural integrity.
[edit] Synthesis
Plutonium metal will spontaneously oxidize to PuO2 in an oxygenic atmosphere at standard temperature and pressure. However, Plutonium(IV) Dioxide is also recovered during the reprocessing of nuclear fuel by calcination of plutonium(IV) oxalate, Pu(C2O4)2.6H2O, at 300 °C.
[edit] 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. As with all plutonium compounds, it is subject to control under the Nuclear Non-Proliferation Treaty.
[edit] See also
[edit] Sources
- Greenwood, N. N.; A. Earnshaw (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
- Space Radioisotope Power Systems Safety
