Question

The complex $ [PtCl_2(en)_2]^{2+} $ ion shows

• A. structural isomerism
• B. geometrical isomerism only
• C. optical isomerism only
• D. geometrical and optical isomerism

Hint:

In complexes with bidentate ligands like ethylenediamine, both geometrical and optical isomerism are commonly observed.

Answer 1

The Correct Option is D

The complex ion $[PtCl_2(en)_2]^{2+}$ exhibits both geometrical and optical isomerism. This is due to its square planar geometry where the coordination number of Pt is 4, and 'en' (ethylene diamine) is a bidentate ligand. Here are the key points regarding the isomerism:

1. Geometrical Isomerism: In a square planar complex, geometrical isomerism arises due to the different possible spatial arrangements of the ligands. For $[PtCl_2(en)_2]^{2+}$, the arrangement of the chloride ions and the two bidentate ethylene diamine ligands can lead to cis and trans isomers.
2. Optical Isomerism: This type of isomerism occurs when a complex is non-superimposable on its mirror image. In this complex, the presence of bidentate ethylene diamine ligands in a specific arrangement can cause the complex to have a chiral center, allowing for optical isomerism where enantiomers (mirror-image isomers) are possible.

Thus, $[PtCl_2(en)_2]^{2+}$ can exist in forms that display both geometrical and optical isomerism. Therefore, the correct answer is geometrical and optical isomerism.

Answer 2

The given complex is \( [PtCl_2(en)_2]^{2+} \), where "en" represents ethylenediamine (a bidentate ligand). The complex has two different types of isomerism:
1. Geometrical isomerism: The complex can show cis-trans isomerism due to the two chloride ions occupying different positions (cis or trans relative to each other).
2. Optical isomerism: Since the complex involves a bidentate ligand (ethylenediamine), the resulting complex can be non-superimposable on its mirror image, leading to optical isomerism.
Thus, the complex exhibits both geometrical and optical isomerism.