Sp bond

The electronic configuration of carbon atom at ground state is different to that of its excited state. At ground state, the electronic configuration of carbon is 1s2 2s2 2px1 2py1.

In the excited state, the electronic configuration of carbon is 1s2 2s1 2px1 2py1 2pz1. However, the carbon atom may not use all its s-orbital and p-orbitals for hybridization. Instead, it may use one s-orbital and two p-orbitals to form three sp2 hybrid orbitals.

If the carbon atom undergoes sp2 hybridization, there would be three sp2 equivalent hybrid orbitals generated. the hybrid orbitals, each holding one electron, would repel one another and take up the shape of a trigonal plane. The angles between the sp2 hybrid orbitals are 120 degree. All the three sp2 hybrid orbitals lie on the single plane. The remaining 2p orbital is orientated perpendicular to this plane.