Chapter 21, Problem 21.73P

Although the carbonyl absorption of cyclic ketones generally shifts to higher wavenumber with decreasing ring size, the $\text{C}=\text{O}$ of cyclopropenone absorbs at lower wavenumber in its $\text{IR}$ spectrum than the $\text{C}=\text{O}$ of $\text{cyclohex-2-enone}$. Explain this observation by using the principles of aromaticity learned in Chapter 17.