Question

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

Answer 1

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 `"C"-"O"` `sigma` bonds (2 from the carboxylic acid group, and 3 from the acetate group)
• 2 non-aromatic `"C"-"C"` `sigma` bonds (1 from the carboxylic acid group, and 1 on the acetate group)
• 6 aromatic `"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 `"C"-"O"` `pi` bonds (1 from the carboxylic acid group, and 1 from the acetate group)
• 3 aromatic `"C"-"C"` `pi` bonds (on the benzene ring)

Thus, we have 5 + 2 + 6 = 13 `\mathbf(sigma)` bonds and 2 + 3 = 5 `\mathbf(pi)` bonds.