How does the spatial arrangement vary in square planar complexes [MX₂L₂], and why is such isomerism not possible in tetrahedral geometry?

In square planar complexes [MX₂L₂], spatial arrangement varies due to geometric isomerism. Isomers can be cis (ligands adjacent) or trans (ligands opposite), influencing properties like dipole moments. In tetrahedral geometry, isomerism is not possible because all positions are equivalent. In square planar complexes, the specific arrangement around the central metal atom allows for distinct spatial orientations, resulting in geometric isomers. The lack of such variability in tetrahedral geometry, where all ligands are equivalent, prevents the occurrence of geometric isomerism in tetrahedral complexes.