How can we calculate bond order from resonating structures?

Dear student,

The bond order of a simple molecule can be determined by looking at the number of electrons in bonding and antibonding molecular orbitals. Like electrons in atomic orbitals , electrons in molecular orbitals fill the lowest energy orbitals first, but no more than two electrons can go in any given MO.

The bond order can then be computed by
0.5*(electrons in bonding orbitals - electrons in antibonding orbitals). (The 0.5 is due to the fact it takes two electrons to make a single bond.)

TOTAL NO RESONATING STRUCTURES DIVIDED BY TOTAL NO OF BONDS INVOLVED IN RESONANCE.