Hybridization is the process of formation of new equivalent orbitals. It is the concept of intermixing of the orbitals of an atom having nearly the same energy to give exactly equivalent orbitals with the same energy, identical shapes and symmetrical orientations in space.
Conditions of Hybridization
(i) Only the orbitals present in the valency shell get hybridized.
(ii) Both filled and half-filled orbitals get hybridized.
(iii) The energy difference between orbitals undergoing hybridization should be small.
(iv) Promotion of electrons is not a must before hybridization takes place.
(v) Hybridization takes place at the time of bond formation only.