Illustrated Glossary of Organic Chemistry

Zwitterion: A molecule having a net formal charge of zero, but negative and positive formal charges on individual atoms within its structure. The charged atoms must be joined by one or more covalent bonds. The charged atoms of NaCl and NH₄Cl are not covalently bonded, so these substances are not zwitterions.


Neutral form Not a zwitterion		Cationic form Not a zwitterion		Anionic form Not a zwitterion		Zwitterionic form

Proton transfer allows glycine to exist in neutral, ionic, and zwitterionic forms.


Neutral resonance contributor Not a zwitterion		Zwitterionic resonance contributor