Neptunium(IV) nitrate is an inorganic compound, a salt of neptunium and nitric acid with the chemical formula Np(NO<sub>3</sub>)<sub>4</sub>. The compound forms gray crystals, dissolves in water, and forms crystal hydrates.
Addition of dilute nitric acid to freshly prepared neptunium(IV) hydroxide:
Neptunium(IV) nitrate forms gray hygroscopic crystals.
It is soluble in water.
It forms a crystal hydrate of the composition Np(NO<sub>3</sub>)<sub>4</sub>â¢2H<sub>2</sub>O.