Promethium(III) nitrate is an inorganic compound, a salt of promethium and nitric acid with the chemical formula Pm(NO3)3.

The compound is radioactive, soluble in water[1] and forms crystalline hydrates.

[2] Reaction of promethium and nitric acid: Promethium(III) nitrate hydrate forms a purple-pink solid.

[2][3] It forms crystalline hydrates of the composition Pm(NO3)3·6H2O.

[4] Promethium(III) nitrate thermally decomposes to form promethium(III) oxide.