Unit – I C – 02

Classification of Alkyl Halides (Contd.):

B) On the Basis of Hybridisation State of the carbon in C-X Bond

i) Compounds containing Csp3 – X Bond:

In this type of monohalo compounds, the halogen atom is directly bonded to sp3 hybridised carbon atom. Such compounds are further classified as follows

a) Haloalkanes or Alkyl Halides:

  • In this type halogen atom is attached to alkyl group denoted by R. Their general formula is CnH2n+1X.
  • They are further classified as primary, secondary and tertiary alkyl halides.
  • If R is alicyclic, then R-X is called halocycloalkane or cycloalkyl halide. Such compounds are either secondary or tertiary.



b) Allylic Halides:

  • The halides in which halogen is attached to  sp3 hybridized carbon atom next to carbon carbon double bond are called allylic halides. Such carbon is called allylic carbon.

  • Note: Allylic halides may be primary, secondary or tertiary.

c) Benzylic Halides:

  • The halides in which halogen is attached to sp3 hybridized carbon atom next to aromatic ring are called benzylic halides. Such carbon is called benzylic carbon.
  • Note: Benzylic halides may be primary, secondary or tertiary.
ii) Compounds containing Csp2 – X Bond:
  • In this type of monohalo compounds, the halogen atom is directly bonded to an sp2 hybridised carbon atom. Such compounds are further classified as

a) Vinylic Halides:

  • The halides in which halogen is attached to one of the sp2 hybridized carbon atom of carbon double bond are called vinylic halide. Such carbon is called vinylic carbon. The halogen atom is attached to one of the carbon atoms of carbon-carbon double bond.

Classification of Alkyl Halides



b) Aryl Halides:

  • In aryl halides, halogen is directly attached to one of the sp2 hybridized carbon atom of benzene ring.

iii) Compounds containing Csp – X Bond:
  • In this type of monohalo compounds, the halogen atom is directly bonded to an sp hybridised carbon atom.

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