Hexafluorophosphoric acid
Hexafluorophosphoric acid is the inorganic compound with the chemical formula H
2FPF
6 (also written H
2F[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]
Names | |
---|---|
IUPAC name
Hydrogen hexafluorophosphate | |
Other names
Hexafluorophosphoric acid | |
Identifiers | |
3D model (JSmol) |
|
ChemSpider | |
ECHA InfoCard | 100.037.263 |
EC Number |
|
PubChem CID |
|
CompTox Dashboard (EPA) |
|
| |
| |
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). | |
![]() ![]() ![]() | |
Infobox references | |
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
3OPF
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
2F
2, H
2PO
2F, and H
3PO
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
References
- Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–74. ISBN 0-8493-0594-2.
- Arpad Molnar; G. K. Surya Prakash; Jean Sommer (2009). Superacid Chemistry (2nd ed.). Wiley-Interscience. p. 44. ISBN 978-0-471-59668-4.
- D. W. Davidson; S. K. Garg (May 1972). "The Hydrate of Hexafluorophosphoric Acid". Canadian Journal of Chemistry. 50 (21): 3515–3520. doi:10.1139/v72-565.