Hexafluorophosphoric acid

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Hexafluorophosphoric acid[1]
Names
IUPAC name
Hydrogen hexafluorophosphate
Other names
Hexafluorophosphoric acid
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.037.263
EC Number 241-006-5
Properties
HPF6
Molar mass 145.972 g/mol
Appearance colorless oily liquid
Melting point decomposes at 25 °C
exists only in solution
Hazards
Main hazards Corrosive
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Hexafluorophosphoric acid is the inorganic compound with the chemical formula H
2
FPF
6
(also written H
2
F[PF
6
]
). This strong Brønsted acid features a non-coordinating anion, hexafluorophosphate (PF
6
). It is formed from the reaction of hydrogen fluoride with phosphorus pentafluoride.[2]

Like many strong acids, hexafluorophosphoric acid is not isolable but is handled only in solution, it exothermically reacts with water to produce oxonium hexafluorophosphate (H
3
OPF
6
) and hydrofluoric acid, both of which are strong acids. Additionally, such solutions often contain products derived from hydrolysis of the P-F bonds, including HPO
2
F
2
, H
2
PO
2
F
, and H
3
PO
4
, and their conjugate bases.[3] Hexafluorophosphoric acid attacks glass. Upon heating, it decomposes to generate HF. Crystalline HPF
6
has been obtained as the hexahydrate, wherein PF
6
is enclosed in truncated octahedral cages defined by the water and protons. NMR spectroscopy indicates that solutions derived from this hexahydrate contain significant amounts of HF.[3]

See also[edit]

References[edit]

  1. ^ Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–74. ISBN 0-8493-0594-2.
  2. ^ Arpad Molnar; G. K. Surya Prakash; Jean Sommer (2009). Superacid Chemistry (2nd ed.). Wiley-Interscience. p. 44. ISBN 0-471-59668-X.
  3. ^ a b D. W. Davidson; S. K. Garg (May 1972). "The Hydrate of Hexafluorophosphoric Acid". Canadian Journal of Chemistry. 50: 3515–3520. doi:10.1139/v72-565.