Explain the structure of [PtCl4]2- and explain why its structure can't be tetrahedral.
Dear student, [PtCl4]2- Complex should be tetrahedral instead of square plane theoretically. But the size of Pt is so large that it forms a strong bond with ligands. Due to which strong repulsion between the electron of pt and ligand takes place which results in strong crystal field splitting.
The strong field splitting breaks the degeneracy of dx2-y2 and dz2 orbital. Hence stabilizes the square planer arrangement more than tetrahedral.
Due to this reason 5th-row and 6th-row transition metals prefer to form square planer complexes.
The above diagram shows the crystal field splitting in square planer complex. Sine the dx2-y2 is empty therefore chlorine donates its lone pair in order to produce dsp2 hybridization which is responsible for the square planer geometry.