Hexafluorophosphoric acid

Hexafluorophosphoric acid^[1]

Names

IUPAC name

Hexafluorophosphoric acid^[2]

Other names

Hydrogen hexafluorophosphate
Hydron hexafluorophosphate

Identifiers

CAS Number

16940-81-1^Y

3D model (JSmol)

Interactive image

ChemSpider

17339451^N

ECHA InfoCard

100.037.263

EC Number

241-006-5

PubChem CID

16211447

CompTox Dashboard (EPA)

DTXSID40884947

InChI

InChI=1S/F6P/c1-7(2,3,4,5)6/q-1/p+1^N
Key: LJQLCJWAZJINEB-UHFFFAOYSA-O^N
InChI=1/F6P/c1-7(2,3,4,5)6/q-1/p+1
Key: LJQLCJWAZJINEB-IKLDFBCSAL

SMILES

[H+].F[P-](F)(F)(F)(F)F

Properties

Chemical formula

HPF₆

Molar mass

145.972 g/mol

Appearance

colorless oily liquid

Melting point

decomposes at 25 °C

Solubility in water

exists only in solution

Hazards

Occupational safety and health (OHS/OSH):

Main hazards

Corrosive

GHS labelling:

Pictograms

Signal word

Danger

Hazard statements

H301, H311, H314, H330

Precautionary statements

P260, P264, P271, P280, P284, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P320, P321, P363, P403+P233, P405, P501

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 refers to a family of salts produced by combining phosphorus pentafluoride and hydrofluoric acid. The idealized chemical formula for hexafluorophosphoric acid is HPF₆, which also is written H[PF]₆.^[3] Hexafluorophosphoric acid is only stable in solution, decomposing to HF and PF₅ when dry.^[4] It exothermically reacts with water to produce oxonium hexafluorophosphate (H₃OPF₆) and hydrofluoric acid. 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.^[5] 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.^[5]

Whereas a species with the formula HPF₆ remains unknown, the analogous molecular hexafluoroarsenic acid (HAsF₆) has been crystallized.^[6]

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.
^ IUPAC. "Nomenclature of Inorganic Chemistry". Retrieved 2021-04-08.
^ Arpad Molnar; G. K. Surya Prakash; Jean Sommer (2009). Superacid Chemistry (2nd ed.). Wiley-Interscience. p. 44. ISBN 978-0-471-59668-4.
^ Lindahl, Charles B.; Mahmood, Tariq (2000), "Fluorine compounds, inorganic, phosphorus", Kirk-Othmer Encyclopedia of Chemical Technology, New York: John Wiley, doi:10.1002/0471238961.1608151912091404.a01, ISBN 9780471238966
^ ^a ^b 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.
^ Axhausen, Joachim; Lux, Karin; Kornath, Andreas (2014). "The Existence of Hexafluoroarsenic(V) Acid". Angewandte Chemie International Edition. 53 (14): 3720–3721. doi:10.1002/anie.201308023. PMID 24446235.