Question
Discuss in brief the various types of hybridisation involving d-orbitals.
Solution
The elements present in the third period contain a-orbitals in addition to s and p orbitals.
The energy of the 3d orbitals is comparable to,
(i) the energy of 3s and 3p orbitals
(ii) the energy of 4s and 4p orbitals.
Hence the hybridization involving either 3s, 3p and 3d or 3d, 4s and 4p is possible. However, since the difference in energies of 3p and 4s orbitals is significant, therefore no hybridization involving 3p, 3d and 4s orbitals is possible.
The hybridisation schemes involving s, p and d orbitals are summarised below:
| Shape of molecules/ions | Hybridisation type | Atomic obritals | Examples |
| Squre planar | dsp2- | d+s+p(2) |
[Ni(CN)4]2–, [Pt(Cl)4]2– |
| Trigonal Bipyramdial | sp3d | s+p(3)+d | PF5.PCl5 |
| Square pyramidal | dsp3 | d+s+p( 3) | BrF5,XeOF4 |
| Octahedral | sp3d2 | s+p(3)+d(2) | SF6,[CrF6]3– |
| d2 sp3 | d(2)+s+p(3) |
[Co(NH3)6]3+ |
