which d-orbital is involved in dsp2 hybradisation
Answers
The dx^2-dy^2 orbital lies in the xy plane with its lobes directed along the x,y axes. The lobes of the px and py orbitals are also directed along the same x,y axes. The dsp2 hybridization favours a planar geometry in which the four hybridized orbitals lie in the equatorial xy plane, as in ICl4- or XeF4. So, the dx^2-dy^2 orbital is used in dsp2 hybridization, along with the s, px and py orbitals to form a square planar geometry.
The dz^2 orbital has its main lobes along the z axis, and its cylindrical collar around the same axis. The sp3d hybridization favours either a trigonal bipyramidal geometry using the dz^2 orbital or a square pyramidal geometry using the dx^2-y^2 orbital. In forming a stable trigonal pyramid, the two axial bonds above and below the equatorial xy plane have to be almost equally strong as the three equatorial bonds, as in PCl5. So, the dz^2 orbital is used, along with the 's' and the three 'p' orbitals, to form three equatorial bonds and two equally strong axial bonds for a trigonal bipyramid.