The
pseudohalogens are polyatomic analogues of
halogens, whose chemistry, resembling that of the true
halogens, allows them to substitute for halogens in several classes of
chemical compounds. Pseudohalogens occur in
pseudohalogen molecules,
inorganic molecules of the general forms
Ps–
Ps or
Ps–X (where
Ps is a
pseudohalogen group), such as
cyanogen;
pseudohalide anions, such as
cyanide ion; inorganic acids, such as
hydrogen cyanide; as
ligands in
coordination complexes, such as
ferricyanide; and as functional groups in organic molecules, such as the
nitrile group. Well-known pseudohalogen functional groups include
cyanide,
cyanate,
thiocyanate, and
azide.
