Bond order is defined as half the difference between the number of bonding and anti-bonding electrons.

Stable bonds have a positive bond order.

**Formula to calculate bond order.**

To calculate the bond order, we start by drawing the **Lewis structure.**

There are different types of bonds between two atoms;

- No bond
- Single bond
- double bond
- triple bond

**Example 1:**

Suppose you are asked to find the bond order of hydrogen gas ( H_{2} ).

The Lewis structure for hydrogen gas is as follows.

**H : H**, this means that only one pair of electrons are shared hence a single bond which also means that hydrogen gas has a bond order of 1.

**Example 2:**

For poly atomic molecules like a nitrate, it is calculated a little bit differently.

We still begin by drawing the Lewis structure of Nitrate.

The total number of bonds in this structure is 4, ( N-0, N-O, N-O, N-O).

While the number of bonding groups is 3, ( N=O, N-O, N-O ).

Therefore, to calculate bond order, we divide the total number of bonds by number of bonds between individual atoms.

= 4 รท 3

= 1.33

Therefore nitrate has a bond order of 1.33.