Illustrated Glossary of Organic Chemistry

Dimer: A structure containing two identical or similar units. These units may be associated by covalent bonding or by noncovalent forces.

Gly-Gly is a dipeptide dimer in which the two amino acid residues are identical (both are glycine). The two units comprising this dimer are attached via a covalent bond.


Gly-Cys is a dipeptide dimer in which the two amino acid residues are very similar (both are amino acids). The two units comprising this dimer are attached via a covalent bond.


Despite its polar covalent bonds, acetic acid has a low dielectric constant. This is because acetic acid forms hydrogen-bonded dimers in which the polar covalent bonds of two acetic acid molecules are opposed.