Hexafluorophosphoric acid

Hexafluorophosphoric acid[1]
Names
IUPAC name
Hexafluorophosphoric acid[2]
Other names
Hydrogen hexafluorophosphate
Hydron hexafluorophosphate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.037.263 Edit this at Wikidata
EC Number
  • 241-006-5
  • 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
  • [H+].F[P-](F)(F)(F)(F)F
Properties
HPF6
Molar mass 145.972 g/mol
Appearance colorless oily liquid
Melting point decomposes at 25 °C
exists only in solution
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Corrosive
GHS labelling:
GHS05: CorrosiveGHS06: Toxic
Danger
H301, H311, H314, H330
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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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]

  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. ^ IUPAC. "Nomenclature of Inorganic Chemistry". Retrieved 2021-04-08.
  3. ^ Arpad Molnar; G. K. Surya Prakash; Jean Sommer (2009). Superacid Chemistry (2nd ed.). Wiley-Interscience. p. 44. ISBN 978-0-471-59668-4.
  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
  5. ^ 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.
  6. ^ 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.