The electronic configurationof carbon in excited state is given as:
6C: 1s2 2s1 2px1 2py1 2pz1
There are four half-filled orbitals available for bond formation resulting in the formation of four covalent bonds in thisstate. However, the four half-filled valence orbitals are not equivalent, there being three p orbitals and one s orbital. To account for the equivalence of the four bonds, it is assumed that the fouravailable orbitals of carbon, the 2s and three 2p orbitals are mixed or hybridized in a manner as to result in four equivalent orbitals (hybridization).Carbon atom can undergo three types of hybridizationin its compounds.
sp3 hybridization (Tetrahedral hybridization)
In this type of hybridization four orbitals (one 2s and three 2p) of the excited carbon atom hybridize to form four orbitals ofequivalent energy and same shape. Each orbital is called sp3 hybrid orbital.
Each of the sp3 hybrid orbitals consists of a big lobe and a very small lobe that has (25%) s-character and (75%)p-character. The four hybrid orbitals are directed towards the corners of a regular tetrahedron. The hybridization is called tetrahedral hybridization and the angle between the hybridized orbitals is 109°28'.
Four sp3 Hybrid Orbitals
sp2 hybridisation (Trigonal hybridisation)
In this type of hybridization, the 2s orbital and two of three 2p orbitals of excited carbon atom hybridize toform three sp2 hybridized orbitals of equivalent energy and identical shape. Each orbital is called sp2 hybrid orbital.
The three sp2 orbitals lie in one plane making an angle of 120° with eachother. A sp2 hybridized carbon is called trigonal carbon atom and the hybridization is known as trigonal hybridization. The unhybridized orbital is orientated in a plane at right angle to the plane...