The square planar complexes with coordination number 4 `(MA_(2)B_(2) or MA_(2)BC)` show geometrical isomerism but tetrahedral complexes do not. Explain.

Explanation

In square planar complexes, out of the four ligands bonded to the central metal atom or ion, two similar ligands are adjacent to one another or they are diagonally opposite to each other. Thus, there are two different geometrical isomerism namely, cis - and trans - isomers.

In tetrahedral complexes `(MA_(2)B_(2), MA_(2)BC, MABCD)`, as there is not difference in the relative positions of the ligands bonded to the central metal atom or ion, they do not show geometrical isomerism.