Protactinium tetrafluoride

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

Protactinium tetrafluoride

Identifiers
CAS Number	61716-26-5 Y
3D model (JSmol)	Interactive image
InChI InChI=1S/4FH.Pa/h4*1H;/q;;;;+4/p-4 Key: CRDGDRUMLTUCQA-UHFFFAOYSA-J
SMILES [Pa+4].[F-].[F-].[F-].[F-]
Properties
Chemical formula	F4Pa
Molar mass	307.02949 g·mol−1
Appearance	dark 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). Infobox references

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 metal is displaced from the salt by barium:

PaF₄ + 2Ba → Pa + 2BaF₂