The compound dissolves in water and forms crystalline hydrates as dark green crystals.
[1][2] 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] 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.
When heated to 150–180 °C, it decomposes with autooxidation to plutonium (VI) with the formation of plutonyl nitrate (PuO2(NO3)2).
Plutonium nitrate is both radioactive and extremely toxic due to its high solubility in water.