Praseodymium(IV) fluoride explained

Praseodymium(IV) fluoride (also praseodymium tetrafluoride) is a binary inorganic compound, a highly oxidised metal salt of praseodymium and fluoride^[1] with the chemical formula PrF₄.

Synthesis

Praseodymium(IV) fluoride can be prepared by the effect of krypton difluoride on praseodymium(IV) oxide:^[2]

PrO _{2} +2KrF _{2} \xrightarrow{ PrF _{4} + O _{2} + 2 Kr }

Praseodymium(IV) fluoride can also be made by the dissolution of sodium hexafluoropraseodymate(IV) in liquid hydrogen fluoride:^[3]

Na _{2[PrF} _{6]} +2HF \xrightarrow{ PrF _{4 \downarrow} + 2 NaHF _{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:

2PrF _{4} \xrightarrow{90 ^{oC} 2 PrF _{3} + F _{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

Notes and References

1. Vent-Schmidt . Thomas . Riedel . Sebastian . Investigation of Praseodymium Fluorides: A Combined Matrix-Isolation and Quantum-Chemical Study . . 18 June 2021 . 11114–11120 . 10.1021/acs.inorgchem.5b01175 . November 6, 2015. 54 . 23 . 26544761 .
2. Book: Meyer . G. . Morss . Lester R. . Synthesis of Lanthanide and Actinide Compounds . 1990-12-31 . . 978-0-7923-1018-1 . 367 . 18 June 2021 . en.
3. Book: Emeléus . H. J. . Sharpe . A. G. . Advances in Inorganic Chemistry and Radiochemistry . 1977-09-01 . . 978-0-08-057869-9 . 368 . 18 June 2021 . en.