Antimony pentafluoride

Antimony pentafluoride (SbF₅) is a colorless, fuming inorganic liquid and powerful Lewis acid. It forms ionic salts with fluoride donors and helps create exceptionally strong acids.

Lewis acid: An electron-pair acceptor that forms a coordinate bond with an electron-pair donor. SbF₅ accepts fluoride and other electron pairs, making it a particularly strong example.
Fluoroantimonic acid: A superacid system formed by combining hydrogen fluoride with antimony pentafluoride. SbF₅ strengthens HF acidity by binding fluoride and generating highly acidic species.
Antimony: A chemical element with symbol Sb and atomic number 51, classified as a metalloid. Antimony is the central atom whose oxidation state and coordination define SbF₅.
Boron trifluoride: A colorless, toxic gas with formula BF₃ that acts as a Lewis acid. BF₃ is a familiar Lewis acid, but SbF₅ has substantially greater fluoride affinity.
Superacid: An acid system stronger than pure sulfuric acid on the Hammett acidity scale. SbF₅ is a standard component used to create and study superacids.
Fluoride ion affinity: A measure of the energy released when a molecule or ion binds a fluoride ion. SbF₅’s high affinity for fluoride underlies its ability to abstract fluoride from donor compounds.
Magic acid: A superacid mixture of fluorosulfuric acid and antimony pentafluoride. This related SbF₅-containing superacid helped establish the chemistry of persistent carbocations.
Fluorine: A highly reactive chemical element with symbol F and atomic number 9. Fluorine atoms bind antimony and account for the compound’s strong fluoride chemistry.
Arsenic pentafluoride: A toxic inorganic compound with formula AsF₅ and a volatile molecular form. AsF₅ is a close Group 15 analogue that offers a comparison of pentafluoride structure and reactivity.
Hammett acidity function: A measure of acidity in highly concentrated or nonaqueous acid systems where ordinary pH is unsuitable. It helps characterize the extreme acidity of mixtures containing SbF₅.

Linked from 5 pages

George Andrew OlahRelated: Its combination with strong Brønsted acids produces media that can stabilize otherwise fleeting ions.