Tetrahedral complexes do not show geometrical isomerismbecause due to symmetrical structure, relative positions of the ligands are same with respect to each other. Square planar complexes of the type MA3B do not show geometrical isomerism because the possible spatial arrangements are equivalent. MABCD type square planar complexes shows three isomers which can be obtained by fixing the position of one ligand and placing any of the remaining three ligands at the trans-position one by one.