Structural isomers determines the attachment or connectivity of their atoms with each other in a given molecular formula. They have different physical and chemical properties. The word isomer is taken from Greek, Iso mean equal and merits means parts.
For example: C2H6O has two structural formula:
Ethanol Dimethyl Ether
Types of Structural Isomers
Basically, there are five types of structural isomers.
- Skeletal or Chain Isomers
- Positional Isomers
- Functional group Isomers
- Metameric Isomers
1. Skeletal or Chain Isomers
Isomers that differ with respect to branching of the carbon skeleton.
For example: C6H14
2. Positional Isomers
This type of isomers differ in the positions of the existed functional group(s).
For example: C3H7-OH
3. Functional Group Isomers
They are different in the types of their functional groups.
For example: Alcohols and Ethers
4. Metameric Isomers
Those isomers having same functional group but attached with different alkyl groups.
For example: Ether with different alkyl groups
This is a special kind of functional group isomerism, where a single molecule can be able to give the reaction properties of two different functional groups. This indicates that such compound occurs as a mixture of two functional group isomers in equilibrium with the other as a result of reversible migration of a hydrogen atom. Such reversible migration of hydrogen atoms will result in change in the functional group.
For Example: Ethyl acetoacetate ester