Plutonium tetroxide

Plutonium tetraoxide

Names
Other names Plutonium(VIII) oxide
Identifiers
3D model (JSmol)	Interactive image
InChI InChI=1S/O2.2O.Pu/c1-2;;;/q-1;;;+1 Key: KOOAIBAKTCSZCC-UHFFFAOYSA-N
SMILES O=[Pu+]=O.O=[O-]
Properties
Chemical formula	PuO4
Molar mass	308 g·mol−1
Solubility in water	insoluble (hydrates)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Plutonium tetraoxide is an inorganic binary compound of plutonium and oxygen with the chemical formula PuO₄. ^[1] This is an exotic, higher-order oxide of plutonium where the metal is in the rare +8 oxidation state. ^{[2] [3]} The compound is volative and very hard to isolate. ^{[4] [5]}

Synthesis

Plutonium tetraoxide may be made by the addition of excess hydrogen peroxide to acidified solutions of plutonium(IV) salt:

Pu(SO₄)₂ + 2H₂O₂ + xH₂O → PuO₄·xH₂O + 2H₂SO₄

Physical properties

Plutonium tetraoxide forms as a crystalline precipitate of light green color, the shades of which vary depending on the impurities of the anions that are captured during precipitation. The precipitate contains impurities of other plutonium oxides, and its actual composition roughly corresponds to the formula PuO_3.5.

It is insoluble in water, and forms crystallohydrates of variable composition PuO₄•xH₂O. Theoretical calculations show that the molecule has the structure (O=Pu=O)⁺(O₂)^-, ^[2] i.e. plutonium is hexavalent and has an oxidation state of +5.

Chemical properties

It decomposes upon heating:

PuO₄ → PuO₂ + O₂

References

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. Huang, Wei; Xu, Wen-Hua; Su, Jing; Schwarz, W. H. E.; Li, Jun (16 December 2013). "Oxidation states, geometries, and electronic structures of plutonium tetroxide PuO4 isomers: is octavalent Pu viable?". Inorganic Chemistry . 52 (24): 14237–14245. doi:10.1021/ic402170q. ISSN   1520-510X. PMID   24274785.
3. Huang, Wei; Pyykkö, Pekka; Li, Jun (8 September 2015). "Is Octavalent Pu(VIII) Possible? Mapping the Plutonium Oxyfluoride Series PuO(n)F(8-2n) (n = 0-4)". Inorganic Chemistry. 54 (17): 8825–8831. doi:10.1021/acs.inorgchem.5b01540. ISSN   1520-510X. PMID   26309065.
4. Zaitsevskii, Andréi; Mosyagin, Nikolai S.; Titov, Anatoly V.; Kiselev, Yuri M. (21 July 2013). "Relativistic density functional theory modeling of plutonium and americium higher oxide molecules". The Journal of Chemical Physics . 139 (3) 034307. Bibcode:2013JChPh.139c4307Z. doi:10.1063/1.4813284. PMID   23883027 . Retrieved 11 January 2026.
5. Koordinat︠s︡ionnai︠a︡ khimii︠a︡ (in Russian). Nauka. 2002. p. 260. Retrieved 11 January 2026.