Chemistry – Organic chemistry - Formulae, functional groups and terminology | e-Consult

Structural isomers are compounds that have the same molecular formula but different structural formulas. This means the atoms are connected in a different order.

C₄H₁₀ (butane) has one structural isomer: CH₃CH₂CH₂CH₃ (butane). This isomer has a straight chain of four carbon atoms.

C₄H₁₀ also has another structural isomer: CH₃CH(CH₃)CH₃ (2-methylpropane or isobutane). This isomer has a branched chain, where one carbon atom is bonded to three other carbon atoms.

For C₄H₈ (but-1-ene), the structural isomers are: CH₃CH=CH₂ (butene) and CH₃CH=CHCH₃ (2-butene). These isomers differ in the position of the double bond within the four-carbon chain.

In summary, structural isomers have the same number and type of atoms but differ in how those atoms are connected. The examples demonstrate how different arrangements of carbon and hydrogen atoms lead to distinct chemical properties.