# How are structural isomers drawn?

Feb 22, 2018

Through many hours of hard practice!

#### Explanation:

Structural isomers have the same molecular formula, but different constitutions (e.g. connectivity of atoms).

Consider,

${C}_{4} {H}_{8} O$ with one degree of unsaturation.

It can have a double bond or a cyclic connection among the carbons (or oxygen, for that matter). I'll draw a few, but there are many constitutional isomers, on average,

That took me five minutes, and I'm sure there are more I missed (like a carbonyl $C = O$ bond among a few of those alkanes).