For the detailed study, organic compounds are classified into different groups and sub groups on the basis of their physical structure and chemical properties. The main classification of organic compounds is given below.
Organic compounds are broadly classified into the following classes:
- Open chain or cyclic compounds: The compounds which contain an open chain system of carbon atoms is called open chain compound. The chains may be straight chains (non-branched) or branched. The open chain compounds are also called aliphatic compounds. The name aliphatic is derived from the Greek word aleiphar meaning fats, as the earlier known compounds of this class were either obtained from animal or vegetable fats, or had fat like character. Example: 1 Butanol, Propane, 2-methyl propane are the examples of open chain compounds. Cyclic compounds are either branch chained or straight chained.
- Closed chain or acyclic (or ring) compounds: The homocyclic compound containing a ring of three or more carbon atoms and resembling aliphatic compounds are called alicyclic compounds. Benzene, anthracene are the examples of closed chain compounds. Closed chain compounds are either homocyclic (compounds containing carbon ring only like benzene)or heterocyclic (compounds containing carbon and other elements in the ring like pyridine, furan etc).