Question

Why doesn't d²sp hybridisation take place? Please explain in detail!

Answer 1

The hybridization involving inner d orbitals (d orbital before s and p orbital) will take place only during formation of complexes by transition elements.
In regular hybridization the inner d orbitals will not be used. In those cases we are having sp3d and sp3d2 hybridization with outer orbital.
In case of formation of complexes with transition metal atom the following points must be considered.

1. Nearly all the transition ions will form complexes with co-ordination number 6 only. Co-ordination number 4 with tetrahedral shape and co-ordination number 4 with square shape are possible only for Nickel, copper and Zinc.
2. Nickle, copper and zinc will only form co-ordination number 4 complexes. For them the hybridization should be between dsp2 and sp3. This is because to get d2sp hybridization we want of 2 empty d orbitals. But nickle, copper and zinc don,t have 2 empty d orbitals.
3. Hence d2sp hybridization is not possible in complexes and hence not possible in any case.