Ionisation Isomerism
Isomers that produce different ions in solution, resulting from the interchange of an ion inside the coordination sphere with an ion outside.
What is Ionisation Isomerism?
A type of structural isomerism in coordination compounds where isomers have the same molecular formula but produce different ions when dissolved in a solvent, due to the interchange of a ligand within the coordination sphere with a counter-ion.
Key points
- Define ionisation isomerism.
- Identify examples of ionisation isomers.
- Explain the cause of ionisation isomerism.
- Differentiate ionisation isomerism from other types of isomerism.
Common exam trap
Confusing ionisation isomerism with linkage isomerism.
Definitions
- Term
Ionisation Isomerism
- Meaning
A type of structural isomerism in coordination compounds where isomers have the same molecular formula but produce different ions when dissolved in a solvent, due to the interchange of a ligand within the coordination sphere with a counter-ion.
- Term
Coordination Sphere
- Meaning
The central metal atom or ion along with the ligands directly bonded to it, enclosed in square brackets in a coordination compound formula.
- Term
Counter-ion
- Meaning
An ion present outside the coordination sphere that balances the charge of the complex ion.
Learning objectives
Define ionisation isomerism.
Identify examples of ionisation isomers.
Explain the cause of ionisation isomerism.
Differentiate ionisation isomerism from other types of isomerism.
Predict the ions produced by ionisation isomers in solution.
Prerequisites
Coordination compounds
Coordination sphere
Ligands
Counter-ions
Dissociation of ionic compounds
Common mistakes
Confusing ionisation isomerism with linkage isomerism.
Not considering the dissociation behaviour of the complex in solution.
Assuming that any difference in ions means ionisation isomerism without checking for the ligand-counter ion exchange.
Incorrectly identifying the coordination sphere and counter-ions.
Keywords
Ionisation Isomerism
Coordination Compounds
Structural Isomerism
Ligand
Counter-ion
Dissociation
Aqueous Solution
NEET Chemistry
Practice preview
Which of the following coordination compounds exhibits ionisation isomerism?…
easy
Which of the following pairs represents ionisation isomers?…
medium
Consider the following complexes: 1. [Co(NH₃)₅Br]SO₄ 2. [Co(NH₃)₅SO₄]Br 3. [Co(NH₃)₄Br₂]Cl 4. [Co(NH₃)₄Cl₂]Br Which of these complexes exhibit ionisation isomerism with each other?…
medium