Classification of organic compounds

Classification of Organic Compounds

Acyclic or open chained compounds:

  • Also called aliphatic compounds.
  • Consist of straight or branched compounds.

Alicyclic or closed chained compounds:

  • Also called aliphatic cyclic.
  • Carbon atoms are bonded in the form of a ring.
  • Homocyclic – consisting only of carbon atoms joined in the ring.
  • Heterocyclic – consist of atoms other than carbon joined in the ring.

Aromatic compounds:

  • Benzenoid: These compounds consist of at least one benzene ring, i.e., a six-membered carbocyclic ring having alternate single and double bonds. Generally, these compounds have some fragrant odour and hence, named as aromatic (Greek word aroma meaning sweet smell).
  • Non-benzenoid aromatics: There are aromatic compounds, which have structural units different from benzenoid type and are known as Non-benzenoid aromatics
    Ex: Tropolone, azulene etc.
    Non Benzenoid aromatics

Functional group:

  • It is an atom or group of atoms responsible for the characteristic chemical properties of the compounds.
    Ex: (-OH) group – alcohol
    (-CHO) group – aldehyde

Homologous series:

  • Compounds containing a common functional group.
  • The successive members differ by a –CH2 unit.
    Ex: Alkanes – methane, ethane, propane
           Alkanols – methanol, ethanol, propanol