Question

Which of the following square planar complexes will show cis-trans isomerism?

[M is the metal while a and b are monodentate ligands.]

• A. $M{a}_4$
• B. $M{a}_{3}b$
• C. $M{a}_2{b}_2$
• D. $Ma{b}_3$

Answer 1

The correct option is C $M{a}_2{b}_2$

Cis-trans isomerism occurs in octahedral and square planar complexes (but not in tetrahedral). When two ligands are adjacent to each other, they are said to be cis and when they are in opposite direction, they are said to be trans.

Of all the above complexes, only $M{a}_2{b}_2$ can have cis-trans geometry.