Neptunium(VII) oxide-hydroxide explained

Neptunium(VII) oxide-hydroxide is a chemical compound which has neptunium in its highest oxidation state of +7. This compound reacts with basic salts such as potassium hydroxide to form neptunates (NpO₅^3-) and water.

NpO₂(OH)₃ + 3KOH → K₃NpO₅ + 3H₂ONeptunium(VII) oxide-hydroxide is stable in an alkaline solution, however, it is slowly reduced to Np(VI) in an acidic solution. In water, it forms a greenish solution.^[1] This compound decomposes slowly to an oxidized solid.^[2]

Production

Neptunium(VII) oxide-hydroxide is produced by the oxidation of Np(VI) in alkaline solution with ozone, then neutralized with nitric acid to precipitate out the neptunium(VII) oxide-hydroxide.

Notes and References

1. V.I.Spitsyn . A.D.Gelman . N.N.Krot . M.P.Mefodiyeva . F.A.Zakharova . Yu.A.Komkov . V.P.ShilovI. . V.Smirnova . Heptavalent state of neptunium and plutonium . Journal of Inorganic and Nuclear Chemistry . 1968 . 31 . 9 . 2733–2745 . 10.1016/0022-1902(69)80187-9 . Institute of Physical Chemistry of the Academy of Sciences of the USSR . English.
2. Book: Robert J. Lemire . Lemire . Robert . Chemical Thermodynamics of Neptunium and Plutonium . 2001 . Elsevier Science . 9780444503794 . 116 . English.