Geometrical Isomerism
Arises from different possible geometric arrangements of ligands around the central metal atom in square planar and octahedral complexes.
What is Geometrical Isomerism?
Stereoisomerism in which compounds have the same molecular formula and connectivity but differ in the spatial arrangement of their atoms or groups.
Key points
- Define geometrical isomerism in coordination compounds.
- Identify complexes exhibiting geometrical isomerism.
- Distinguish between cis and trans isomers.
- Draw possible geometrical isomers for given square planar and octahedral complexes.
Common exam trap
Confusing geometrical isomerism with linkage isomerism or ionization isomerism.
Definitions
- Term
Geometrical Isomerism
- Meaning
Stereoisomerism in which compounds have the same molecular formula and connectivity but differ in the spatial arrangement of their atoms or groups.
- Term
Cis Isomer
- Meaning
An isomer where similar ligands are adjacent to each other (at an angle of 90° in octahedral and square planar complexes).
- Term
Trans Isomer
- Meaning
An isomer where similar ligands are opposite to each other (at an angle of 180° in octahedral and square planar complexes).
Learning objectives
Define geometrical isomerism in coordination compounds.
Identify complexes exhibiting geometrical isomerism.
Distinguish between cis and trans isomers.
Draw possible geometrical isomers for given square planar and octahedral complexes.
Prerequisites
Coordination compounds: Central metal atom, ligands, coordination number.
Valency and oxidation states.
Types of ligands (monodentate, bidentate).
Basic understanding of isomerism (constitutional vs. stereoisomerism).
Common mistakes
Confusing geometrical isomerism with linkage isomerism or ionization isomerism.
Assuming geometrical isomerism in tetrahedral complexes (due to free rotation).
Incorrectly identifying cis and trans positions in complex octahedral structures.
Not considering the type of ligands (e.g., bidentate ligands affecting isomerism).
Keywords
Geometrical Isomerism
Coordination Compounds
Stereoisomerism
Square Planar Complexes
Octahedral Complexes
Cis Isomer
Trans Isomer
Ligand Arrangement
Practice preview
Which of the following types of complexes exhibits geometrical isomerism?…
easy
In which of the following octahedral complexes can geometrical isomerism be observed?…
medium
Which of the following statements about geometrical isomerism in coordination compounds is INCORRECT?…
hard