3.2.5.3 Shapes of complex ions

• Transition metal ions commonly form octahedral complexes with small ligands (eg H2O and NH3).
• • Octahedral complexes can display cis–trans isomerism (a special case of E–Z isomerism) with monodentate ligands
  • Optical isomerism with bidentate ligands
• Transition metal ions commonly form tetrahedral complexes with larger ligands (eg Cl– ).
• • Square planar complexes are also formed and can display cis–trans isomerism.
  • ie Cisplatin
  • Cisplatin is the cis isomer
• Ag+ forms the linear complex [Ag(NH3)2] + as used in Tollens’ reagent.