The bond order of a diatomic molecule can be calculated using the molecular orbital (MO) theory formula:

Bond order=Number of electrons in bonding orbitals−Number of electrons in antibonding orbitals2\text{Bond order}=\frac{\text{Number of electrons in bonding orbitals}-\text{Number of electrons in antibonding orbitals}}{2}Bond order=2Number of electrons in bonding orbitals−Number of electrons in antibonding orbitals​

Given that the molecule has 8 electrons in bonding orbitals and 3 electrons in antibonding orbitals, the bond order is:

8−32=52=2.5\frac{8-3}{2}=\frac{5}{2}=2.528−3​=25​=2.5

Thus, the bond order of this molecule is 2.5

. A bond order of 2.5 indicates a bond strength between a double and a triple bond, implying a relatively strong bond but slightly weaker than a full triple bond. This calculation aligns with the standard approach in molecular orbital theory, where electrons in antibonding orbitals reduce the overall bond strength