Praseodymium(IV) fluoride

Praseodymium(IV) fluoride (also praseodymium tetrafluoride) is a binary inorganic compound, a highly oxidised metal salt of praseodymium and fluoride with the chemical formula PrF₄.

Synthesis

Praseodymium(IV) fluoride can be prepared by the effect of krypton difluoride on praseodymium(IV) oxide:

$𝖯𝗋{𝖮}_{\mathrm{𝟤}}\mathsf{+}\mathrm{𝟤}𝖪𝗋{𝖥}_{\mathrm{𝟤}}\stackrel{}{\to }𝖯𝗋{𝖥}_{\mathrm{𝟦}}\mathsf{+}{𝖮}_{\mathrm{𝟤}}\mathsf{+}\mathrm{𝟤}𝖪𝗋$

Praseodymium(IV) fluoride can also be made by the dissolution of sodium hexafluoropraseodymate(IV) in liquid hydrogen fluoride:

$𝖭{𝖺}_{\mathrm{𝟤}}\mathsf{[}𝖯𝗋{𝖥}_{\mathrm{𝟨}}\mathsf{]}\mathsf{+}\mathrm{𝟤}𝖧𝖥\stackrel{}{\to }𝖯𝗋{𝖥}_{\mathrm{𝟦}}\mathsf{\downarrow }\mathsf{+}\mathrm{𝟤}𝖭𝖺𝖧{𝖥}_{\mathrm{𝟤}}$

Properties

Praseodymium(IV) fluoride forms light yellow crystals. The crystal structure is anticubic and isomorphic to that of uranium tetrafluoride UF₄. It decomposes when heated:

$\mathrm{𝟤}𝖯𝗋{𝖥}_{\mathrm{𝟦}}\stackrel{90^{o}C}{\to }\mathrm{𝟤}𝖯𝗋{𝖥}_{\mathrm{𝟥}}\mathsf{+}{𝖥}_{\mathrm{𝟤}}$

Due to the high normal potential of the tetravalent praseodymium cations (Pr3+ / Pr4+: +3.2 V), praseodymium(IV) fluoride decomposes in water, releasing oxygen, O₂.

See also

• Praseodymium(III) fluoride
• Uranium tetrafluoride