What is Fluoroantimonic acid?

Fluoroantimonic acid is a mixture of hydrogen fluoride and antimony penta­fluoride, containing various cations and anions. This substance is a superacid that can be in excess of a quadrillion times stronger than 100% pure sulfuric acid, depending on the proportion of its ingredients. It has been shown to protonate even hydro­carbons to afford pentacoordinate carbo­cations. Extreme care must be taken when handling and storing fluoro­antimonic acid, as it is exceptionally corrosive. For example, it cannot be contained directly in glass carboys, as it will dissolve glass, but can be stored in containers lined with PTFE.