There are basically three structural isomers of pentane.1) First isomer is the simple straight chain isomer with no branching. It has the following structureCH3-CH2-CH2-CH2-CH3Its IUPAC name is simply pentane and common name is n-pentane.2) The second isomer has a branched methyl group. It has the following structureCH3-CH(CH3)-CH2-CH33) The third isomer is also a branched isomerIts IUPAC name is 2,2-dimethylpropane and common name is neopentane.

Pentane is an organic compound with the molecular formula C5H12. It belongs to the alkane family, which means it consists of only single bonds between carbon atoms. Structural isomers are compounds with the same molecular formula but different structural arrangements. In the case of pentane, we can draw several structural isomers.

Linear Pentane
The simplest form of pentane is a straight-chain or linear isomer, also known as n-pentane. It has a straight chain of five carbon atoms with the chemical formula CH3(CH2)3CH3.

Branching Isomers
Branching isomers are formed by substituting one or more hydrogen atoms in the linear pentane chain with alkyl groups.

1. Isopentane (Methylbutane)
Isopentane is an isomer of pentane with a branched structure. It has four carbon atoms in a chain with one methyl group (CH3) attached to the second carbon atom.

2. Neopentane (Dimethylpropane)
Neopentane is another branched isomer of pentane. It consists of a central carbon atom bonded to four methyl groups (CH3).

3. Other Isomers
Besides the linear and branching isomers mentioned above, there are additional structural isomers of pentane that can be drawn by rearranging the carbon chain or altering the position of substituents. These isomers include:

- 2-Methylbutane: It has a linear carbon chain with one methyl group attached to the second carbon atom.
- 2,2-Dimethylpropane: It consists of a central carbon atom connected to three methyl groups.
- 3-Methylbutane: It has a linear carbon chain with one methyl group attached to the third carbon atom.
- 2,3-Dimethylbutane: This isomer has a linear carbon chain with two methyl groups attached to the second and third carbon atoms.

These are the main structural isomers of pentane. Each of these isomers has a unique arrangement of carbon atoms and hydrogen atoms, leading to different physical and chemical properties.