Plutonium(IV) nitrate explained

Plutonium (IV) nitrate is an inorganic compound, a salt of plutonium and nitric acid with the chemical formula Pu(NO₃)₄. The compound dissolves in water and forms crystalline hydrates as dark green crystals.^{[1] [2]}

Synthesis

Crystals of dark green to black-green composition Pu(NO₃)₄•5H₂O precipitate with a slow (months) evaporation of a solution of a plutonium (IV) compound in nitric acid.^{[3] [4]}

Physical properties

Plutonium (IV) nitrate forms a crystalline hydrate of the composition Pu(NO₃)₄•5H₂O—dark green crystals of rhombic crystal structure, space group F dd2, cell parameters: a = 1.114 nm, b = 2.258 nm, c = 1.051 nm, Z = 8.

Crystalline hydrate melts in its own crystallization water at 95–100 °C.

It dissolves well in nitric acid (dark green solution) and water (brown solution). Also dissolves in acetone and ether.

Chemical properties

When heated to 150–180 °C, it decomposes with autooxidation to plutonium (VI) with the formation of plutonyl nitrate (PuO₂(NO₃)₂).Upon evaporation of concentrated nitric acid solutions of plutonium nitrate and alkali metal nitrates, double nitrates of the composition Me₂[Pu(NO₃)₆] are formed, where Me = Cs⁺, Rb⁺, K⁺, Tl⁺, NH₄⁺, analogous to ceric ammonium nitrate.

Toxicity

Plutonium nitrate is both radioactive and extremely toxic due to its high solubility in water.

Notes and References

1. Allen . P. G. . Veirs . D. K. . Conradson . S. D. . Smith . C. A. . Marsh . S. F. . Characterization of Aqueous Plutonium(IV) Nitrate Complexes by Extended X-ray Absorption Fine Structure Spectroscopy . . January 1996 . 35 . 10 . 2841–2845 . 10.1021/ic9511231 . 16 August 2021.
2. Kubic . William . Jackson . J. . A thermodynamic model of plutonium (IV) nitrate solutions . . 9 March 2012 . 293 . 2 . 601–612 . 10.1007/s10967-012-1703-4 . 94704456 . 16 August 2021 . 1588-2780.
3. Baroncelli . F. . Scibona . G. . Zifferero . M. . The extraction of Pu(IV) nitrate by long chain tertiary amines nitrates . . 1 November 1962 . 24 . 5 . 541–546 . 10.1016/0022-1902(62)80241-3 . 16 August 2021 . en . 0022-1902.
4. Nakahara . Masaumi . Kaji . Naoya . Yano . Kimihiko . Shibata . Atsuhiro . Takeuchi . Masayuki . Okano . Masanori . Kuno . Takehiko . Nitric Acid Concentration Dependence of Dicesium Plutonium(IV) Nitrate Formation during Solution Growth of Uranyl Nitrate Hexahydrate . Journal of Chemical Engineering of Japan . 16 August 2021 . 56–62 . 10.1252/jcej.12we175 . 2013. 46 .