Structural and Stereo Isomerism
Isomers share a molecular formula but differ in connectivity (structural isomerism) or spatial arrangement (stereoisomerism).
What is Structural and Stereo Isomerism?
Isomers share a molecular formula but differ in connectivity (structural isomerism) or spatial arrangement (stereoisomerism).
Key formula / rule: Chain, position and functional isomerism are structural forms.
Key points
- Classify isomers as structural or stereoisomers.
- Identify chiral centres and the number of stereoisomers.
Common exam trap
Labelling a carbon chiral when two attached groups are identical.
Definitions
- Term
Structural and Stereo Isomerism
- Meaning
Isomers share a molecular formula but differ in connectivity (structural isomerism) or spatial arrangement (stereoisomerism).
- Term
Structural and Stereo Isomerism — explanation
- Meaning
Chirality requires a carbon with four different groups, and the resulting enantiomers differ only in their interaction with other chiral entities. Geometrical isomerism needs restricted rotation.
Learning objectives
Classify isomers as structural or stereoisomers.
Identify chiral centres and the number of stereoisomers.
Formulae
- Key point
Chain, position and functional isomerism are structural forms.
- Key point
Enantiomers are non-superimposable mirror images.
- Key point
Geometrical isomerism requires restricted rotation and two different groups on each carbon.
Prerequisites
CHE-U4-GO-T1-S1-C1
Common mistakes
Labelling a carbon chiral when two attached groups are identical.
Confusing cis-trans with E-Z priority assignment.
Keywords
Structural
Stereo
Isomerism
Practice preview
Which of the following pairs represents chain isomers?…
easy
Propanone and Propanal are examples of which type of structural isomerism?…
easy
Which of the following conditions is NOT required for a compound to exhibit geometrical isomerism?…
medium