Question

Which one of the following complex ions has geometrical isomers?

Option 1: \(\left[\text{Co}(\text{Cl})_2(\text{en})_2\right]^+\)

Option 2: \(\left[\text{Cr}(\text{NH}_3)_4(\text{en})\right]^{3+}\)

Option 3: \(\left[\text{Co}(\text{en})_3\right]^{3+}\)

Option 4: \(\left[\text{Ni}(\text{NH}_3)_5\right]\text{Br}\)

• A. \(\left[\text{Co}(\text{Cl})_2(\text{en})_2\right]^+\)
• B. \(\left[\text{Cr}(\text{NH}_3)_4(\text{en})\right]^{3+}\)
• C. \(\left[\text{Co}(\text{en})_3\right]^{3+}\)
• D. \(\left[\text{Ni}(\text{NH}_3)_5\right]\text{Br}\)

Hint:

Geometrical isomerism occurs when ligands in a coordination compound can arrange in different spatial configurations, leading to distinct isomers.

Answer 1

The Correct Option is A

The complex ion \(\left[\text{Co}(\text{Cl})_2(\text{en})_2\right]^+\) exhibits geometrical isomerism. This is because the two ethylenediamine (\(\text{en}\)) ligands and the two chloride (\(\text{Cl}\)) ligands can arrange themselves in different spatial orientations, leading to cis-trans isomerism.