Chapter 5.4, Problem 5.6E

Using orbital potential energies, show that group orbital 4 is more likely than group orbital 2 to interactstrongly with the ${\text{2p}}_z$ orbital of carbon.
The $2p_y$ orbital of carbon has $B_{2u}$ symmetry and interacts with group orbital 5 (Figure 5.23). Theresult is the formation of two $\pi$ molecular orbitals, one bonding and one antibonding. However, there isno carbon orbital with $B_3{}_g$ symmetry to interact with group orbital 6, also formed by combining $2p_y$
orbitals of oxygen. Therefore, group orbital 6 is nonbonding.