Question

The complex $[Cr(NH_3)_4Cl_2]^+$ shows how many geometrical isomers?

• A. 1
• B. 2
• C. 3
• D. 4

Hint:

For octahedral complexes of the type $[MA_4B_2]$, only cis and trans forms are possible geometrical isomers.

Answer 1

The Correct Option is B

The octahedral complex [Cr(NH₃)₄Cl₂]⁺ features four ammonia (NH₃) ligands and two chloride (Cl) ligands. Octahedral complexes display geometrical isomerism when at least two distinct ligand types bind to the metal center. This complex, containing NH₃ and Cl ligands, exhibits two possible isomers based on the spatial arrangement of the Cl ligands:

• Cis isomer: The two Cl ligands are positioned adjacent to each other in the octahedral structure.
• Trans isomer: The two Cl ligands are positioned opposite each other in the octahedral structure.

Consequently, the [Cr(NH₃)₄Cl₂]⁺ complex can exist as 2 geometrical isomers: cis and trans.

Geometrical Isomers
Cis
Trans

In summary, the complex exhibits 2 geometrical isomers.