Cyclic compound

In chemistry, a cyclic compound is a compound in which a series of atoms is connected to form a loop or ring. While the vast majority of cyclic compounds are organic, a few inorganic substances form cyclic compounds as well, including sulfur, silanes, phosphanes, phosphoric acid, and triboric acid. Cyclic compounds may or may not be aromatic. Benzene is a well known example. The term "polycyclic" is used when more than one ring is formed in a single molecule for instance in naphthalene, and the term macrocycle is used for a ring containing more than a dozen atoms.

Categorization
Cyclic compounds can be categorized:
 * Alicyclic compound
 * Cycloalkane
 * Cycloalkene
 * Aromatic hydrocarbon
 * Polycyclic aromatic hydrocarbon
 * Heterocyclic compound
 * Macrocycle

Ring-closing & opening reactions
Related concepts in organic chemistry are so-called ring-closing reactions in which a cyclic compound is formed and ring-opening reactions in which rings are opened.

Examples of ring-closing reactions: Example of ring-opening reactions:
 * Ring-closing metathesis
 * Nazarov cyclization reaction
 * Ruzicka large ring synthesis
 * Dieckmann condensation
 * Wenker synthesis
 * Radical cyclization
 * A general type of polymerization reaction: Ring-opening polymerization
 * Ring opening metathesis polymerisation