Neptunium trioxide

Neptunium trioxide
Names
Other names
Neptunium(VI) oxide
Identifiers
Properties
NpO3
Molar mass 285 g·mol−1
Appearance dark brown crystals (hydrate)
insoluble
Related compounds
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Neptunium trioxide is an inorganic compound of neptunium and oxygen with the chemical formula NpO3.

Synthesis

Neptunium trioxide can be obtained by oxidating neptunium(V) nitrate solution in a molten eutectic mixture of potassium and lithium nitrates with ozone at 150 °C. The reaction by-products are washed out with water. Other methods are also known.

Physical properties

Neptunium trioxide is highly volatile and exists only in the hydrated form. It is insoluble in water. It forms dark brown hydrate crystals of variable composition NpO3•xH2O, where x = 1–2. The NpO3•H2O hydrate crystals are of orthorhombic system.

References

  1. ↑ Domanov, V. P. (1 August 2009). "Formation of volatile neptunium trioxide NpO3 and two other products of neptunium oxidation". Radiochemistry. 51 (4): 350–353. doi:10.1134/S1066362209040031. ISSN 1608-3288. Retrieved 17 October 2025.
  2. ↑ Morss, L. R.; Edelstein, Norman M.; Fuger, Jean (31 December 2007). The Chemistry of the Actinide and Transactinide Elements (3rd ed., Volumes 1-5). Springer Science & Business Media. p. 770. ISBN 978-1-4020-3598-2. Retrieved 17 October 2025.
  3. ↑ Lemire, Robert J. (26 August 2001). Chemical Thermodynamics of Neptunium and Plutonium. Elsevier. p. 118. ISBN 978-0-444-50379-4. Retrieved 17 October 2025.
  4. ↑ Plutonium Abstracts. Hanford Laboratories. 1964. p. 8. Retrieved 17 October 2025.
  5. ↑ Bagnall, K. W.; Laidler, J. B. (1 January 1964). "516. Neptunium and plutonium trioxide hydrates". Journal of the Chemical Society (Resumed) (0): 2693–2696. doi:10.1039/JR9640002693. ISSN 0368-1769. Retrieved 17 October 2025.