Noun
zwitterion (plural zwitterions)
(chemistry) A molecule, such as an amino acid, that carries both a positive and a negative charge.
Glycine may exist as a zwitterion at the isoelectric point, but the equilibrium constant for the isomerization reaction in solution :H 2 NCH 2 CO 2 H ⇌ H 3 N + CH 2 CO 2 − is not known. Source: Internet
Sulfamic acid isomers, with the zwitterion (right). Source: Internet
The isomer on the right is a zwitterion. Source: Internet