Macrocycle

In chemistry, especially organic chemistry, a macrocycle is a molecule made of a large ring of atoms. According to IUPAC, the term means a cyclic macromolecule, but is also used by many chemists to describe cyclic compounds that are smaller than macromolecules but larger than simple cycles.

The exact number of atoms where a cycle becomes a macrocycle is not firmly defined. One common definition is a cyclic compound where the cycle has twelve or more atoms in it. This matches a drop in ring strain in the cycloalkanes, as cyclododecane and larger rings can assume more stable shapes than the medium-weight rings (cyclooctane through cycloundecane).

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