Protactinium tetrafluoride

Protactinium tetrafluoride is a binary inorganic compound of protactinium metal and fluorine with the chemical formula PaF4.[1]

Protactinium tetrafluoride
Identifiers
3D model (JSmol)
  • InChI=1S/4FH.Pa/h4*1H;/q;;;;+4/p-4
    Key: CRDGDRUMLTUCQA-UHFFFAOYSA-J
  • [Pa+4].[F-].[F-].[F-].[F-]
Properties
F4Pa
Molar mass307.02949 g·mol−1
Appearancedark brown crystals
Related compounds
Related compounds
Uranium tetrafluoride, neptunium tetrafluoride, plutonium tetrafluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Synthesis

Protactinium tetrafluoride can be obtained by fluorinating protactinium(IV) oxide with a hydrogen fluoride / hydrogen mixture at 600 °C:

PaO2 + 4HF → PaF4 + 2H2O

The effect of hydrogen fluoride and hydrogen on protactinium(V) oxide:

Pa2O5 + 8HF + H2 → 2PaF4 + 5H2O

Physical properties

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]

Chemical properties

Protactinium tetrafluoride reacts with oxygen and fluorine:[2]

2PaF4 + F2 → 2PaF5
4PaF4 + O2 → 2Pa2OF8

The compound reacts with alkalis:

PaF4 + 4NaOH → PaO2 + 4NaF + 2H2O

The compound is displaced from the salt by barium:

PaF4 + 2Ba → Pa + 2BaF2

References