Plutonium trioxide

Plutonium trioxide
Names
	Other names Plutonium(VI) oxide
Identifiers
CAS Number	12311-78-3 ;
3D model (JSmol)	Interactive image;
	InChI InChI=1S/H2O.3O.Pu/h1H2;;;;/q;3*-2;+6 Key: XKRCXWINTGBBQF-UHFFFAOYSA-N;
	SMILES [Pu+6].[O-2].[O-2].[O-2].O;
Properties
Chemical formula	PuO3
Molar mass	536 g·mol−1
Appearance	golden-red crystals (hydrates)
Solubility in water	insoluble (hydrates)
Related compounds
Other anions	Uranium trioxide; Neptunium trioxide;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Plutonium trioxide is an inorganic compound of plutonium and oxygen with the chemical formula PuO₃.^[1] This is a high-order oxide of plutonium where the metal is in the +6 oxidation state. The compound is less stable and less common than the common plutonium dioxide PuO₂.^{[citation needed]}

Theoretical calculations on molecular actinide trioxides predict that while molecular plutonium trioxide should attain the +6 oxidation state for plutonium, the molecular trioxides of the heavier actinides should be regarded as having the actinide in the +5 oxidation state^[2]

Synthesis

Initially, plutonium(III) hydroxide is obtained, which then transforms into plutonium(IV) hydroxide in air, and then oxygen containing ozone is passed through the suspension:^[3]

Pu(OH)₄ + O₃ → PuO₃·H₂O + O₂ + H₂O

Physical properties

Plutonium trioxide forms hydrates of variable composition PuO₃·xH₂O, where x = 0.8–1, which are golden-red crystals.^[4] Not isolated in the anhydrous state: it decomposes when attempted to separate the water.^{[citation needed]}

Chemical properties

Decomposes when heated:^[5]

2 PuO₃·xH₂O → 2 PuO₂ + O₂ + 2x H₂O

References

↑ May, Iain; Bryan, N. D.; Alvares, Rebeca (31 October 2007). Recent Advances In Actinide Science. Royal Society of Chemistry. p. 275. ISBN 978-1-84755-536-6. Retrieved 11 January 2026.
↑ Zaitsevskii, Andréi (14 October 2015). "Plutonium and transplutonium element trioxides: molecular structures, chemical bonding, and isomers". Physical Chemistry Chemical Physics. 17 (38): 24831–24836. Bibcode:2015PCCP...1724831Z. doi:10.1039/c5cp02190a. ISSN 1463-9084. PMID 26343514.
↑ Bagnall, K. W.; Laidler, J. B. (1 January 1964). "516. Neptunium and plutonium trioxide hydrates". Journal of the Chemical Society (Resumed): 2693–2696. doi:10.1039/JR9640002693. ISSN 0368-1769. Retrieved 11 January 2026.
↑ Lemire, Robert J. (26 August 2001). Chemical Thermodynamics of Neptunium and Plutonium. Elsevier. p. 339. ISBN 978-0-444-50379-4. Retrieved 11 January 2026.
↑ Structural Chemistry of Inorganic Actinide Compounds. Amsterdam; Oxford: Elsevier. 2007. p. 491. ISBN 978-0-444-52111-8. Retrieved 11 January 2026.

[1] May, Iain; Bryan, N. D.; Alvares, Rebeca (31 October 2007). Recent Advances In Actinide Science. Royal Society of Chemistry. p. 275. ISBN 978-1-84755-536-6. Retrieved 11 January 2026.

[2] Zaitsevskii, Andréi (14 October 2015). "Plutonium and transplutonium element trioxides: molecular structures, chemical bonding, and isomers". Physical Chemistry Chemical Physics. 17 (38): 24831–24836. Bibcode:2015PCCP...1724831Z. doi:10.1039/c5cp02190a. ISSN 1463-9084. PMID 26343514.

[3] Bagnall, K. W.; Laidler, J. B. (1 January 1964). "516. Neptunium and plutonium trioxide hydrates". Journal of the Chemical Society (Resumed): 2693–2696. doi:10.1039/JR9640002693. ISSN 0368-1769. Retrieved 11 January 2026.

[4] Lemire, Robert J. (26 August 2001). Chemical Thermodynamics of Neptunium and Plutonium. Elsevier. p. 339. ISBN 978-0-444-50379-4. Retrieved 11 January 2026.

[5] Structural Chemistry of Inorganic Actinide Compounds. Amsterdam; Oxford: Elsevier. 2007. p. 491. ISBN 978-0-444-52111-8. Retrieved 11 January 2026.

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