MO diagrams and Bond order [ENDORSED]

[Katrina_Domingo_3G]

To calculate the bond order of a molecule, do we always have to draw the molecular orbital diagram or is there a simpler way to calculate it?? Thank you!

[Adriana Muro 1A]

you don't have to do MO necessarily, i think if you draw the lewis structure it should work the same to calculate bond order

[Pauline Tze 3B]

I highly recommend calculating bond order primarily through MO diagram. If you do lewis structure, you'll miss it if the bond order is not a whole number (like 0.5 or 2.5). This is because the bond order equation specifically asks for 1/2( # bonding orbitals + # anti-bonding orbitals) and you can't account for anti-bonding orbitals with merely a lewis structure.

However, if you do want a shortcut, I find that If you practice the molecular electron configuration enough times, you can remember the order of sigma and pi bonds for both versions of the MO diagram (z<8 and z=>8) and calculate bond order for any molecule that way.

Hope that helps!