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sp2 hybridisation

When a C atom is attached to 3 groups and so is involved in 3 σ bonds, it requires 3 orbitals in the hybrid set. This requires that it is sp2 hybridised. The general "steps" are similar to that for seen previously sp3 hybridisation.

sp2 hybridisation
  • "Blend" (i.e. hybridise) the s and the 2 p orbitals...
    • since we "mixed" 3 orbitals, we get a set of 3 sp2 orbitals
    • the other p orbital remains unaffected
    • each sp2 hybrid and the p orbital contains a single unpaired electron
You can view an animation of the hybridisation of the C orbitals if you wish.

  • In ethene, H2C=CH2
    • both C are sp hybridised.
    • 4 C-H σ bonds are made by the interaction of C sp2 with H1s orbitals (see red arrows)
    • 1 C-C σ bond is made by the interaction of C sp2 with another C sp2 orbital (see green arrow)
    • 1 C-C π bond is made by the interaction of the C p with the other C p orbital (see black arrows)
orbitals to bonds for ethene


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organic chemistry © Dr. Ian Hunt, Department of Chemistry University of Calgary