Question

Which type of isomerism is exhibited by the following complex? \[ [Pt(NH_3)_2Cl_2] \]

Hint:

Square planar complexes often show cis–trans isomerism. Classic example: \([Pt(NH_3)_2Cl_2]\) (cisplatin).

Answer 1

Step 1: Understanding the Complex.
The given complex is \( [Pt(NH_3)_2Cl_2] \), where platinum (Pt) is the central metal ion, coordinated with two ammonia (\(NH_3\)) molecules and two chloride (\(Cl^-\)) ions.

Step 2: Type of Isomerism.
This complex exhibits geometrical isomerism, also known as cis-trans isomerism.

- Cis isomer: The two chloride ions are adjacent to each other (on the same side of the platinum ion).
- Trans isomer: The two chloride ions are opposite each other (on opposite sides of the platinum ion).

Step 3: Explanation of Isomerism.
Geometrical isomerism arises in square planar complexes when the ligands can be arranged in different spatial orientations. In this case, since the complex is square planar, the chloride ions can either be next to each other (cis) or across from each other (trans), leading to two possible isomers.

Conclusion.
The complex \( [Pt(NH_3)_2Cl_2] \) exhibits geometrical isomerism (cis-trans isomerism) due to the different possible spatial arrangements of the chloride ligands.