Discuss the different types of hybridisation in s and p atomic orbitals
These are of three types:
(i) sp3-type (Tetrahedral hybridisation)
(ii) sp2-type (Trigonal hybridisation)
(iii) sp-type (Diagonal hybridisation)
(i) sp3 hybridisation : Electronic configuration of carbon (Z=6) in the excited state is 1s2
. This type of hybridisation involves the mixing of all the four half filled orbitals. i.e. one s and three p orbitals to form four new orbitals called sp3 hybrid orbitals of equivalent energies and identical shapes.
Fig. Representation of sp3 hybridisation
The four sp3 hybrid orbitals are directed towards the four corners of a tetrahedral. The angle between two adjacent sp3 hybrid orbitals is of 109° – 28'. Each sp3 hybrid orbital has 1/4 s-character and p-character. sp3 hybridisation is also known as tetrahedral hybridisation.
Examples of compounds in which sp3-hybridisation takes place are:
(a) All saturated compounds of carbon such as alkanes, cycloalkanes etc.
(b) Water, alcohols, ethers, ammonia and amines.
(ii) sp2 hybridisation: The electronic configuration of carbon (Z = 6) in the excited state is 
. In this type of hybridisation one s and two p-orbtials of the valence shell of carbon atom take part in hybridisation to give three new sp2 hybrid orbitals. These sp2 hybrid orbitals lie in a plane and are directed towards the corners of an equilateral triangle with carbon atom in the centre. The unhybridised 
orbital lies perpendicular to the three hybridised orbitals, three hybridised orbitals.
sp2 hybridisation is also known as trigonal hybridisation. Each sp2 hybrid orbital has 1/3 s-character and 2/3 p-character.
Examples of compounds in which sp2- hybridisation takes place are:
(a) All compounds of boron i.e. BF3, BH3 etc.
(b) All compounds of carbon containing C=C double bonds such as alkenes, arenes etc.
(iii) sp-hybridisation. The electronic configuration of carbon atom (Z = 6) in the excited state is 
In this type of hybridisation, one s and one p orbital of valence shell of carbon atom take part in hybridisation to give two sp hybrid orbitals of equivalent energies and shape. These sp hybrid orbitals are directed in space at an angle of 180° with respect to each other. Therefore, sp hybridisation is also called linear hybridisation or diagonal hybridisation. Each sp-hybrid orbital has 1/2 s-character and 1/2 p-character. The two unhybridised orbitals (2p and 2pz) which are left lie in different planes at right angles to each other and also to the plane of hybridised orbitals.
Examples of compounds in which sp-hybridisation takes place are:
(i) All compounds of carbon containing C ≡ C and C ≡ N triple bonds.
(ii) All compounds of beryllium such as BeF2, BeH2 etc.
