Hybridization dsp3 orbitals

Thus the central iodine is dsp3 hybridized. Three of these hybrid orbitals hold lone pairs, and two of them overlap with sp3 orbitals from the other two iodine atoms to form cr bonds. 

Although it will not be important for our purposes, the dsp3 hybrid orbital set is different from the hybrids we have considered so far in that the hybrid orbitals pointing to the vertices of the triangle (often called the three equatorial hybrid orbitals) are slightly different in shape than the other two (the axial orbitals). This situation stands in contrast to the sp, sp1, and sp3 hybrid sets in which each orbital in a particular set is identical in shape to the others. 

For a d1 ion such as Co2+, an additional possibility exists. The electron configuration of Co2+ is 3d7 so if the seven electrons in the 3d orbitals are forced to occupy four orbitals, one orbital is empty. Therefore, a set of dsp3 hybrids can form, and this is the hybrid orbital type for a trigonal bipyramid. This is exactly the behavior exhibited in the complex [Co(CN)5]3  

Lastly, we consider a system with non-equivalent positions. An example of such a system is the trigonal bipyramidal molecule AX5 with symmetry. As discussed previously, one possible scheme is the dsp3 hybridization, where dz2 is the only d orbital participating. 

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