Question

Which one of the following Coordination entities exhibits Facial and Meridional isomerism?

• A. \([Co(H_2O)_3(NO_3)_3]\)
• B. \([Co(en)_3Cl]^+\)
• C. \([Co(NH_3)_4]Br_2NO_3\)
• D. \([Co(en)_3]Cl_3\)

Hint:

In coordination 6256d60dc6a8bca7110c99d1, always focus on the geometry of the complex and the arrangement of ligands to identify the possible isomerisms like facial, meridional, and optical isomerism.

Answer 1

The Correct Option is A

- Facial isomerism occurs when three identical ligands are arranged in a facial position, i.e., forming a 90° angle on the same side of the coordination sphere. - Meridional isomerism occurs when three identical ligands are arranged in a meridional position, i.e., occupying positions around the coordination sphere forming an angle of 180°. - Option (A): The compound \([Co(H_2O)_3(NO_3)_3]\) exhibits both Facial and Meridional isomerism. The water and nitrate ions can be arranged in these two distinct geometries, leading to different isomers. - Option (B): The complex \([Co(en)_3Cl]^+\) does not show Facial and Meridional isomerism. It exhibits optical isomerism, as the ligands are chiral but there is no room for facial and meridional arrangements. - Option (C): The complex \([Co(NH_3)_4]Br_2NO_3\) does not exhibit facial and meridional isomerism. The geometry does not allow such isomerism due to the arrangement of ligands. - Option (D): Similarly, \([Co(en)_3]Cl_3\) is a coordination complex where the ligands are arranged symmetrically, but it does not exhibit facial or meridional isomerism.