The term superacid was originally coined by James Bryant Conant in 1927 to describe acids that were stronger than conventional mineral acids.
In 1994 the Nobel Prize in Chemistry was awarded to George A. Olah for his investigations of superacids and their use in the direct observation of carbocations. "Olah's magic acid," so-named for its ability to attack hydrocarbons, is prepared by mixing antimony pentafluoride (SbF5) and fluorosulfuric acid. The name was coined after one of Professor Olah's post-doctoral associates placed a candle in a sample of magic acid. The candle was dissolved, showing the ability of the acid to protonate hydrocarbons, which under normal acidic conditions do not protonate to any extent.
The strongest known superacid is fluoroantimonic acid (HSbF6), a mixture of hydrogen fluoride and antimony pentafluoride. It is rapidly and explosively decomposed by water, and reacts with virtually all known solvents.
Fluoroantimonic acid is approximately 2×1019 (20 quintillion) times stronger than pure sulfuric acid.