N-Phenylsydnone, so-named because it was first studied at the University of Sydney, Australia, behaves like a typical aromatic molecule. Explain, using the Hückel 4n 1 2 rule.

See figure 1

Explanation:

In this question, we have to check the five-carbon ring. In this ring, we have a double bond between the nitrogen atoms a double bond between carbons 10 and 11. Finally, inside the ring, we have a pair of oxygen number 9. These are the electrons that are involved in the resonance.  (See figure 1)

So, how many electrons we have?

Double bond N/N = 2 electrons

Double bond C/C = 2 electrons

Lone pair from oxygen= 2 electrons

In total, we will have 6 electrons. Lets apply the huckle rule:

4n+2=6

n=(6-2)/4

n=1

We obtain a whole number for this molecule, therefore the molecule complies with the huckel rule.

I hope it helps!