A solvent with a comparatively high
relative permittivity (or
dielectric constant), greater than
ca. 15, and a sizable permanent
dipole moment, that cannot donate suitably
labile hydrogen atoms to form strong hydrogen bonds, e.g. dimethyl sulfoxide. The term (and
its alternative '
polar aprotic solvent') is a misnomer and is therefore discouraged. Such solvents are usually not
aprotic but
protophilic (and at most weakly
protogenic). In describing a solvent it is better to be explicit about its essential properties,
e.g. dipolar and non-protogenic.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1106