How many sigma/pi bonds are in the aspirin structure?

May 1, 2016

Aspirin is the brand name for acetylsalicylic acid, which is the common name for 2-(acetyloxy)benzoic acid. This compound looks like this:

In a single bond, you have a single $\sigma$ bond.

In a double bond, there is one $\pi$ bond in addition to the single $\sigma$ bond that constituted the single bond.

Thus, if we treat each double bond as a single bond on this structure, we count up the $\sigma$ bonds as:

• 5 $\text{C"-"O}$ $\sigma$ bonds (2 from the carboxylic acid group, and 3 from the acetate group)
• 2 non-aromatic $\text{C"-"C}$ $\sigma$ bonds (1 from the carboxylic acid group, and 1 on the acetate group)
• 6 aromatic $\text{C"-"C}$ $\sigma$ bonds (on the benzene ring)

Then, in accounting for the particular bonds that are double bonds, the remaining $\pi$ bonds are from:

• 2 $\text{C"-"O}$ $\pi$ bonds (1 from the carboxylic acid group, and 1 from the acetate group)
• 3 aromatic $\text{C"-"C}$ $\pi$ bonds (on the benzene ring)

Thus, we have 5 + 2 + 6 = 13 $\setminus m a t h b f \left(\sigma\right)$ bonds and 2 + 3 = 5 $\setminus m a t h b f \left(\pi\right)$ bonds.