Constitutional isomers

CONSTITUTIONAL ISOMERS

Key Notes

Introduction

Isomers are compounds which have the same molecular formula, but differ in the way the atoms are arranged. There are three types of isomers – constitutional, configurational, and conformational.

Definition

Constitutional isomers are compounds which have the same molecular for-mula but have the atoms joined together in a different way. Constitutional isomers have different physical and chemical properties.\

Alkanes

Alkanes of a particular molecular formula can have various constitutional isomers. The larger the alkane, the more isomers which are possible.

Introduction

Isomers are compounds which have the same molecular formula (i.e. they have the same atoms), but differ in the way these atoms are arranged. There are three types  of  isomers  –  constitutional  isomers,  configurational  isomers,  and conformational isomers. Constitutional isomers are isomers where the atoms arelinked together in a different skeletal framework and are different compounds.Configurational isomers are structures having the same atoms and bonds, butwhichhave different geometrical shapes which cannot be interconverted withoutbreaking  covalent  bonds.  Configurational  isomers  can  be  separated  and  are different  compounds  with  different  properties.  Conformational  isomers  are different shapes of the same molecule and cannot be separated.

Definition

Constitutional isomers are compounds which have the same molecular formula but have the atoms joined together in a different way. In other words, they have different carbon skeletons. Constitutional isomers have different physical and chemical properties.   

Alkanes

Alkanes of a particular molecular formula can exist as different constitutional isomers. For example, the alkane having the molecular formula C4H10 can exist as two constitutional isomers – the straight chain alkane (butane) or the branched alkane (2-methylpropane; Fig. 1). These are different compounds with different physical and chemical properties.