Organic compounds in which carbon atoms are joined in a ring, unlike the open-chain counterparts, are represented using the polygon formula. These cyclic polygons do not show carbon and hydrogen atoms. The corner of a polygon represents a carbon atom with its required number of hydrogen atom(s), and the sides of the polygon represent a carbon-carbon bond.
If an atom or a group of atoms other than carbon and hydrogen is attached to a carbon centre, then that atom or a group of atoms is shown in the structure.
For example,