Structural Isomerism
Isomers differing in the connectivity of atoms or ligands to the central metal ion.
What is Structural Isomerism?
Isomerism in which compounds have the same molecular formula but differ in the connectivity of atoms or ligands to the central metal ion.
Key points
- Define structural isomerism in coordination compounds.
- Identify and differentiate between various types of structural isomers (linkage, ionization, hydrate, coordination).
- Explain the basis of structural isomerism with examples.
- Predict the possibility of structural isomerism in given coordination compounds.
Common exam trap
Confusing structural isomerism with stereoisomerism (geometric and optical).
Definitions
- Term
Structural Isomerism
- Meaning
Isomerism in which compounds have the same molecular formula but differ in the connectivity of atoms or ligands to the central metal ion.
- Term
Linkage Isomerism
- Meaning
A type of structural isomerism where a ligand can coordinate to the metal ion through different donor atoms (e.g., NO2- can coordinate as -NO2 or -ONO).
- Term
Ionization Isomerism
- Meaning
A type of structural isomerism where the counter ion of a complex can also act as a ligand, and vice versa, leading to different ions in solution.
- Term
Hydrate Isomerism
- Meaning
A type of structural isomerism in which water molecules are present as coordinated ligands or as lattice water, and their positions can be interchanged.
- Term
Coordination Isomerism
- Meaning
A type of structural isomerism that occurs when two complex ions in a compound can exchange ligands, leading to different complex species.
Learning objectives
Define structural isomerism in coordination compounds.
Identify and differentiate between various types of structural isomers (linkage, ionization, hydrate, coordination).
Explain the basis of structural isomerism with examples.
Predict the possibility of structural isomerism in given coordination compounds.
Prerequisites
Coordination compounds and their nomenclature.
Valency and oxidation states of metal ions.
Nature of ligands (monodentate, bidentate, ambidentate).
Basic understanding of chemical bonding.
Common mistakes
Confusing structural isomerism with stereoisomerism (geometric and optical).
Incorrectly identifying the donor atom in ambidentate ligands.
Not considering the role of counter ions in ionization isomerism.
Overlooking the possibility of water molecules acting as ligands.
Keywords
Structural Isomerism
Coordination Compounds
Linkage Isomerism
Ionization Isomerism
Hydrate Isomerism
Coordination Isomerism
Ambidentate Ligands
Central Metal Ion
Connectivity
Practice preview
Consider the complex [Co(en)₂(NH₃)Cl]²⁺. Which of the following is an ionisation isomer of this complex?…
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Coordination isomerism occurs when...…
easy
Which of the following complexes exhibits hydrate isomerism?…
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