A medium having a high
acidity, generally greater than that of 100 wt.% sulfuric acid. The common superacids are
made by dissolving a powerful
Lewis acid
(e.g.
SbF5) in a suitable
Brønsted acid
such as
HF or
HSO3F.
(An equimolar mixture of
HSO3F and
SbF5
is known by the trade name '
magic acid'.) In a biochemical context '
superacid catalysis' is sometimes used to denote
catalysis by metal ions analogous to
catalysis by hydrogen ions. By analogy, a compound having a very high
basicity, such as lithium diisopropylamide, is called a '
superbase'.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1169