Protactinium(V) oxide is a chemical compound with the formula Pa₂ O₅. When it is reduced with

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

, it forms PaO₂. Aristid V. Grosse was first to prepare 2 mg of Pa₂O₅ in 1927. Pa₂O₅ does not dissolve in concentrated HNO₃, but dissolves in HF and in a HF + H₂SO₄ mixture and reacts at high temperatures with solid oxides of alkali metal and

alkaline earth metal The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are all ...

s.Boris F. Myasoedov, H. W. Kirby, & Ivan G. Tananaev (2006) Protactinium, Chapter 4 in Morss, Lester R. & Edelstein, Norman M. & Fuger, Jean, (edit.
The Chemistry of the Actinide and Transactinide Elements
(PDF) (3. painos). Dordrecht: Springer. ss. 161–252. As protactinium(V) oxide, like other protactinium compounds, is radioactive, toxic and very rare, it has very limited technological use. Mixed oxides of Nb, Mg, Ga and Mn, doped with 0.005–0.52% Pa₂O₅, have been used as high temperature dielectrics (up to 1300 °C) for ceramic capacitors.

References

Oxides Protactinium compounds {{Inorganic-compound-stub