Question

The bond order of ${\mathrm{B}}_2$ molecule is_______?

Answer 1

Bond order:

• The bond order is known to show the number of chemical bonds present between a pair of atoms.
• Molecular orbital diagrams generally help in determining the bond order of the molecule.
• Hence the formula used for bond order calculation can be given as:

$\text{Bond order}=\frac{1}{2}\left[\right(\text{Number of electrons in BMO})-\left(\text{Number of electrons in ABMO}\right)]$

The bond order of ${\mathrm{B}}_2$ molecule:

• The ${\text{B}}_{\text{2}}$ molecule is known to be formed by the combination of two Boron atoms, where they are linked by a covalent bond.
• The atomic number of boron is 5, for which the electronic configuration of boron can be given as:$1s^{2}2s^{2}2p^1$
• The molecular orbital diagram for ${\text{B}}_{\text{2}}$ molecule can be shown as :
  

• From the diagram, we can know that the number of electrons in bonding molecular orbitals is 4 whereas the number of electrons in antibonding molecular orbitals is 2.
• Hence, the bond order is calculated as:

$$\begin{gathered} \text{Bond order}\text{=}\frac{1}{2}\left(4-2\right) \\ \text{= 1} \end{gathered}$$

Thus, the bond order for ${\text{B}}_{\text{2}}$ molecule is found to be$1.$