Protactinium tetrafluoride is a binary inorganic compound of protactinium metal and fluorine with the chemical formula PaF4.

[1] Protactinium tetrafluoride can be obtained by fluorinating protactinium(IV) oxide with a hydrogen fluoride / hydrogen mixture at 600 °C: The effect of hydrogen fluoride and hydrogen on protactinium(V) oxide: PaF4 forms dark brown, monoclinic, needlelike crystals of UF4 structure.

[2][3] The cell parameters are: a = 1.27 nm, b = 1.07 nm, c = 0.842 nm, β = 126.3°.

The compound is soluble in aqueous ammonium fluoride solutions.

[4] Protactinium tetrafluoride reacts with oxygen and fluorine:[2] The compound reacts with alkalis: The metal is displaced from the salt by barium: