Cyclic compound
= Cyclic compound
A <cyclic compound> contains at least one closed sequence of bonded atoms. Rings can contain only carbon or include heteroatoms, and can be saturated, unsaturated, aromatic, fused, bridged, or spiro-connected.
For example, cyclohexane is a saturated carbocycle and pyridine is an aromatic heterocycle. Ring size and connectivity constrain conformation and strain, so cyclicity provides structural information beyond a molecular formula.