||Chapter 2 :
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.
- "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
You can view an animation
of the hybridisation of the C orbitals if you wish.
- In ethene, H2C=CH2
- both C are sp2 hybridised.
- 4 C-H σ bonds are made by the interaction
of C sp2 with H1s orbitals (see red
- 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
- sp2 occurs when a C has 3 attached
- sp2 has 33% s and 67% p character
- the 3 sp2 hybrids point towards the
corners of a triangle at 120o to each other
- each sp2 hybrid is involved in a σ
- the remaining p orbital forms the π bond
- view a double bond as a σ + π bond