How Many Structural Isomers are Possible for Butane

Introduction

There are two structural isomers possible for butane. A structural isomer of a compound is another compound whose molecules have the same number of atoms of each element but with different bonds between them. The atoms are arranged in a different order with the same molecular formulas. Structural isomerism or constitutional isomerism is a kind of isomerism in which the molecules have the same molecular formula with different orders and bonds.

Structural Isomers of Butane

Butane is an alkane that is made up of four carbon atoms. Alkanes are the simplest forms of hydrocarbons with all C-C bonds. They are also known as saturated hydrocarbons. Their general formula is C_{n}H_{2n+2} . The formula of Butane is hence C_{4}H_{10} . Butane exhibits structural isomerism. There are two possible structural isomers of butane which are:

1. n-Butane

2. Isobutane

n-Butane is a straight-chain four-carbon compound in which the atoms are bonded with single covalent bonds. The formula of n-Butane is the same as Butane which is C_{4}H_{10} .

The structure of n-Butane is depicted as CH_{3}-CH_{2}-CH_{2}-CH_{3} .

Isobutane on the other hand is also a four-carbon compound but it has a different structure. In isobutane, three carbon atoms form the parent chain while one carbon atom is placed as the side chain at the second carbon of the parent chain. The formula of isobutane is also the same as Butane which is C_{4}H_{10} . The IUPAC nomenclature of isobutane is 2-methylpropane. The structure of isobutane is depicted as CH_{3}-CH(CH_{3})-CH_{3} .

Conclusion

There are two structural isomers possible for butane. These are n-Butane and isobutane. Both of these isomers have the molecular formula C_{4}H_{10} . They have the same molecular formula but differ in their structure.