Question

Giving suitable examples, discuss the geometrical isomerism shown by the following type of complex:

[Ma₂bc]^n±

Answer 1

• The complex of the type [Ma₂bc]^n± shows geometrical isomerism due to the spatial arrangement of different ligands around the central metal ion in a square planar.
• In this type of complex, there are four ligands: two identical ligands (a), and two different ligands (b and c). Such isomerism is observed primarily in square planar complexes, especially those formed by d⁸ metal ions.
• Geometrical isomerism affects the dipole moment, color, solubility, and reactivity of the complex.
• For example, the cis and trans forms of complex diamminebromidochloridoplatinum (II), [PtBrCl(NH₃)₂]. 
  Cis-isomer: Both NH₃ ligands are adjacent to each other. 
  Trans-isomer: Both NH₃ ligands are opposite to each other.