What is Zwitterion

A zwitterion is a molecule that carries both positive and negative electrical charges, resulting in a net charge of zero. The term "zwitterion" comes from the German word "zwitter," meaning hermaphrodite or hybrid, reflecting the dual nature of the charges in the molecule.

Zwitterions often form in substances with both acidic and basic functional groups, which can donate and accept protons (H+ ions). In a zwitterionic form, the molecule has an internal ion pair, with a positive charge on one part of the molecule and a negative charge on another.

An example of a zwitterion is the amino acid. Amino acids are the building blocks of proteins and contain both an amino group (-NH2), which can act as a base and accept a proton, and a carboxyl group (-COOH), which can act as an acid and donate a proton. In the zwitterionic form, the amino group is protonated, carrying a positive charge, and the carboxyl group is deprotonated, carrying a negative charge, resulting in a net charge of zero for the entire molecule.

The ability of certain molecules to exist as zwitterions has implications in various fields, including biochemistry and medicinal chemistry.