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Bond Order Formula

Last updated date: 24th Apr 2024
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What is the Bond Order Formula?

Chemistry is concerned with the process through which subatomic particles combine to form atoms. Bond order is critical in molecular orbital theory for determining bond strength and is also used in valence bond theory. 

The bond order of a molecule is a measure of the number of electrons participating in bonds between two atoms. It is used to determine the stability of a connection. 

Concept of Bond Order

The bond order concept was first introduced by Linus Pauling. The disparity between the number of bonds and antibonds is what defines it.

The bond number is the number of electron pairs that exist between two atoms. The higher the bond order, the more powerful the bond. 

Bond order is often sufficient for the number of bonds between two atoms. There are exceptions when a molecule comprises antibonding orbitals.

It is the measure of the stability of the molecule. The stability of the molecule also depends on the type of bonds. The electronic configuration of the atoms determines the bond order. There is a well-established bond order formula to calculate bond order. It is important to study the formula to find bond order to look into the structure of different compounds and calculate their stability. Let us learn more about bond orders in this chapter.

The bond order of a single covalent bond between two atoms is one, a double bond is two, a triple bond is three, and so on.

Follow these methods to discover the bond order between two covalently bonded atoms:

Create a Lewis structure.

Determine the nature of the bonds that exist between the two atoms.

0: No bond exists.

1: Single bond

2: double bond

3: triple bond

The molecule cannot form if the bond order is zero. Higher bond orders suggest that the new molecule will be more stable.

The bond order in molecules with resonance bonding does not have to be an integer.

Bond Formula - Structure

The average bond order formula considers the number of electrons on the bonding and the antibonding orbitals. It is defined as half of the difference between them. The bond order equation is

Bond order =\[\frac{1}{2}[N_{b}-N_{a}]\]

Where Nb is the number of electrons in the bonding orbitals

And Na is the number of electrons in the antibonding orbitals.

A simpler way to find the bond order is to calculate the number of bonds between the atoms. For example, for N≡N, the bond order is 3.  

Bond Order - Reaction

How is a Bond Order Determined in a Chemical Reaction?

In a chemical reaction between two atoms, the bond order is determined by the number of electrons participating in bond formation. The atoms can interact to form covalent or ionic bonds. In Ionic bonds, electrons are transferred from one atom to another. Covalent bonds involve the sharing of electrons between two atoms. 

The electronic configuration of the atoms determines the bond order. For example, in a Carbon molecule, four bonds are shared between the two carbon atoms. Both the carbon atoms require four electrons to complete their octet. Therefore, the bond order in a carbon molecule is 4. Similarly, the bond order for nitrogen molecules is 3 and oxygen is 2.


The s shell of hydrogen atoms has one electron, and the s shell can accommodate two electrons. 

When two hydrogen atoms form a bond, each completes the other's shell. There are two bonding orbitals generated. 

There are no electrons compelled to migrate to the next higher orbital, the p shell, resulting in the formation of antibonding orbitals. 

The bonding order = Display style (2-0)/2 = 1, is the bonding order. Hence, the molecule H2 (hydrogen gas) is formed as a result of this reaction.

What is the Importance of Bond Order?

It is important to study the bond order formula in chemistry. It helps us to understand several factors contributing to the formation of the compound. Some of them are:

Bond order helps us to know the number of participating electrons in the formation of bonds.

  • Bond order helps us to understand the stability of the bond. Higher bond order confers more stability.

  • Bond order helps us to understand the bond length.

  • Bond order helps us to understand bond strength. Higher bond order implies more energy is required to break the bond.

  • Bond order gives us an indication of the hybridization of the molecule.

  • A fractional bond order value implies that no bond is formed.


The concept of bond order has been studied for several years. Bond order is determined by the number of bonding and antibonding electrons. People use the bond order formula to find out the bond. Various properties of the bond can be known from bond order values.

FAQs on Bond Order Formula

1. What are the steps to determine bond order?

If there are more than two atoms in the molecule, the bond order can be determined by following the procedures below:

  1. Make a design of the Lewis structure.

  2. Then, the total number of bonds is to be counted.

  3. Individual atoms are linked together by bond groups, which can be counted.

  4. To calculate the total number of bonds between atoms:

Divide the number of bonds between atoms by the total number of bond groups in the molecule.

2. What are the three different types of bonds that can exist within a molecule, and what factors determine the bond type?

Three types of bonding are commonly used: ionic, covalent, and metallic. 

It is possible to build an ionic bond when valence electrons are transferred from one atom to another to complete the outer electron shell. 

Example: NaCl (salt) is a common example of an ionically bound material.

Also, the sort of covalent bond established between two atoms is determined by the number of pairs of electrons shared between them.

3. Is bond order important to study? If yes, why?

In chemistry, it is critical to study the bond order formula. It aids us in comprehending the various factors that contribute to the formation of the compound. Among them are:

  • Bond order tells us how many electrons are involved in the formation of a bond.

  • Bond order helps us understand the bond's stability. More stability is conferred by higher bond order.

  • Bond order aids in understanding bond length.

  • Bond order aids in understanding bond strength. A higher bond order indicates that more energy is needed to break the bond.

  • The order of the bonds indicates the degree of hybridization of the molecule.

  • A fractional bond order value denotes the absence of a bond.

4. How many types of bonds are there in chemistry and what explains the Ionic bond?

Ionic, covalent, hydrogen bonds, and Van Der Waals interactions are the four types of bonding. 

Strong ionic and covalent bonds take more energy to break apart. A positive ion is generated when an element donates an electron from its outer shell.

Because positive and negative charges attract, ions stick together to create an ionic bond. The electrons from one element bond with the other element. 

An electron from the sodium atom stays with the other seven electrons from the chlorine atom, resulting in a net-zero charge ion lattice when Na+ and Cl ions combine to produce NaCl.

5. What is Van Der Waals interaction?

It takes its name from the Dutch scientist Johannes Diderik Van Der Waals. He first discovered these forces in 1873 while working on a theory about the properties of real gases.

Van der Waals interactions, like hydrogen bonds, are weak interactions between molecules. They happen between polar, covalently bound atoms in various molecules.


Some of these weak attractions are caused by the formation of temporary partial charges as electrons move around a nucleus. In biological systems, these weak interactions between molecules are important.