https://doi.org/10.1351/goldbook.H02740
A
Lewis acid
with an acceptor centre of low polarizability
. Other things being approximately equal, complexes of hard acids and bases
or soft acids and bases have an added stabilization (sometimes called 'HSAB' rule). For example the hard O- (or N-) bases are preferred to their S- (or P-) analogues by hard acids. Conversely a soft acid
possesses an acceptor centre of high polarizability
and exhibits the reverse preference for coordination
of a soft base
. These preferences are not defined in a quantitative sense.See also:
class (a) metal ion