Preferred Label : mesoionic compounds;
IUPAC definition : Dipolar five- (possibly six-) membered heterocyclic compounds in which both the negative
and the positive charge are delocalized, for which a totally covalent structure cannot
be written, and which cannot be represented satisfactorily by any one polar structure.
The formal positive charge is associated with the ring atoms, and the formal negative
charge is associated with ring atoms or an exocyclic nitrogen or chalcogen atom. Mesoionic
compounds are a subclass of betaines.;
Origin ID : M03842;
See also
Dipolar five- (possibly six-) membered heterocyclic compounds in which both the negative
and the positive charge are delocalized, for which a totally covalent structure cannot
be written, and which cannot be represented satisfactorily by any one polar structure.
The formal positive charge is associated with the ring atoms, and the formal negative
charge is associated with ring atoms or an exocyclic nitrogen or chalcogen atom. Mesoionic
compounds are a subclass of betaines.
