Magic acid

Magic acid is a superacid mixture of fluorosulfuric acid and antimony pentafluoride. It protonates exceptionally weak bases, including hydrocarbons.

Fluorosulfuric acid: A strong Brønsted acid with formula HSO₃F, used as a component of superacid mixtures. It supplies the protons whose activity rises sharply when antimony pentafluoride is added.
Stable carbocation: A carbocation sufficiently long-lived to be detected or studied under specified conditions. Magic acid can generate persistent carbocations from hydrocarbons for spectroscopic study.
George A. Olah: A Hungarian-American chemist whose work established the use of superacids to study carbocations. His research group developed magic acid and used it to investigate protonated hydrocarbons.
Fluoroantimonic acid: A superacid system formed from hydrogen fluoride and antimony pentafluoride. It shares antimony pentafluoride with magic acid but uses hydrogen fluoride instead of fluorosulfuric acid.
Antimony pentafluoride: A strong Lewis acid with formula SbF₅ that readily accepts fluoride ions. It binds fluoride from fluorosulfuric acid, strengthening the mixture's ability to donate protons.
Carbonium ion: A carbocation in which a carbon atom forms more than three bonds, often through a C–H or C–C bond. Superacid protonation can produce these unusual, highly coordinated carbon species.
Superacid chemistry: The study of reactions and species in acids stronger than pure sulfuric acid. Magic acid became a central medium in the expansion of this field.
Sulfuric acid: A strong mineral acid with formula H₂SO₄, widely used in industry and laboratories. It provides the familiar reference point exceeded by superacids such as magic acid.
Superacid: An acid stronger than pure sulfuric acid, measured using acidity functions or related methods. Magic acid is a defining example of this unusually strong class of acids.
Methanium ion: The CH₅⁺ ion, a fluxional carbonium ion with five hydrogen atoms bonded around carbon. It is a striking example of a species formed by protonating methane in superacid conditions.

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George Andrew OlahBroader topic: Olah used this exceptionally strong acid medium to create and stabilize reactive carbocations.