zwitterion
Sign in to saveIn chemistry, a zwitterion ( ; ), also called an inner salt or dipolar ion is a molecule that contains an equal number of positively and negatively charged functional groups. (1,2-dipolar compounds, such as ylides, are sometimes excluded from the definition.)
Article
8 sectionsContents
- Examples
- Case studies
- Amino acids
- Betaines and similar compounds
- Nucleotides
- Conjugated zwitterions
- See also
- References
In chemistry, a zwitterion ( ; ), also called an inner salt or dipolar ion is a molecule that contains an equal number of positively and negatively charged functional groups. (1,2-dipolar compounds, such as ylides, are sometimes excluded from the definition.)
Some zwitterions, such as amino acid zwitterions, are in chemical equilibrium with an uncharged "parent" molecule. Betaines are zwitterions that cannot isomerize to an all-neutral form, such as when the positive charge is located on a quaternary ammonium group. Similarly, a molecule containing a phosphonium group and a carboxylate group cannot isomerize.