Protactinyl nitrate, protactinium(V) oxynitrate, or erroneously known as protactinium nitrate, is a radioactive chemical compound with the formula PaO(NO3)3·xH2O (1.5 ≤ x ≤ 4). It is a white solid that readily hydrolyzes to protactinium(V) oxide in moist air. This compound is a common commercial source of protactinium.[1]
Protactinyl nitrate was first prepared in 1966 by reacting protactinium(V) chloride or protactinium(V) bromide with fuming nitric acid. Lower concentrations of nitric acid cannot be used, due to the hydrolysis of the compound.
Protactinyl nitrate decomposes at 400 °C to protactinium(V) oxide.