Superacids: A brief review.

This article presents an overview of the superacids' chemistry. Superacids constitute a special class of acids much stronger than the usual mineral acids. In the last thirty years the interest in these systems has increased substantially, with emphasis on organic synthesis. The superacids can be useful as catalysts of several reactions not possible by using common catalysts. For example, methane, known by its chemical inertness, can be activated in a HSO3F/SbF5 medium to undergo an electrophilic oligocondensation. Some methods to evaluate acidity of superacids are briefly discussed, together with the correspondent experimental techniques.