How To Calculate Formal Charge In Chemistry

How To Calculate Formal Charge In Chemistry

There is a formal charge present in polyatomic molecules, which refers to the charges held by each of the atoms in turn. It is important to realize that fraudulent charges contribute to only a single atom of the structure.

In the structure of a molecule or compound, the actual charge is distributed throughout the entire structure, and this is the real charge, as opposed to the fake charge. The presence of defects in the configuration of at least one atom participating in the chemical reaction is required to produce a formal charge.

It is important to understand how to calculate the formal charge, and that’s exactly what we will discover in the next chapter. We then discuss the formal charge formula, how to calculate the formal charge, as well as other aspects related to the formal charge. I believe formal charge gives a good introduction to chemistry.

Formula To Find Out Formal Charge

As a final step toward understanding what is meant by formal charge, let’s examine the formal charge formula in more depth. According to a mathematical perspective, the formal charge can be understood like this:

FC= VE – 0.5BE – NBE


FC = Formal Charge

VE = Valence Electrons

BE = Bonding Electrons

NBE = Non-Bonding Electrons

The value of all electrons in a bond held between two electrons will be halved if two electrons attach.

The purpose of this part of the article is to show you how we can determine the formal charge of a polyatomic molecule by examining an example to demonstrate our point. Once we have the formal charge formula, we can proceed to the example.

Calculate Formal Charge Of Sulphur Dioxide

Two electrons attached, therefore, cannot bond to one another for a bond to exist, and as a consequence, the value of each electron will be halved. Hence, the covalent bonding of two electrons won’t be possible.

Here we will discuss how to determine the formal charge of a polyatomic molecule that we have examined in the previous article. We will use an example to demonstrate our point in this part of the article. First, we need to come up with a formal charge formula before we can proceed with the example.

how to calculate the formal charge
how to calculate the formal charge

Numbers 1,2,3,4 Indicate The Index of the Oxygen Atom.

AtomValence electrons in the free stateNo. of non-bonding electrons in Lewis structureNo. of pairs of bonding electrons in Lewis structureFormal Charge
Sulphur (S)60126 – 0 – 12/2 = 0
Oxygen (O) – 16446 – 4 – 4/2 = 0
Oxygen (O) – 26626 – 6 – 2/2 = -1
Oxygen (O) – 36446 – 4 – 4/2 = 0
Oxygen (O) – 46626 – 6 – 2/2 = -1


For more information on how to calculate the formal charge of SO2 in the same way that it is calculated with regards to CO2, please see the example above.

The formal charge is a physical property that describes how molecules or ions behave, and it is calculated using the Lewis structure and subsequent formal charge of the molecule or ion, followed by applying the formula for calculating formal charge.

Importance Of Formal Charge In Chemistry

After we’ve understood what formal charge is, and we’ve familiarized ourselves with the calculation of formal charge, we will talk about what formal charge is and its significance in the section below.

  • As a chemist, I find that formal charge is an invaluable concept when I have to study molecules at very close quarters. In contrast, there does not appear to be any charge separation between individual molecules. Formal charges are different from those of charges in terms of their nature, so you must understand their differences.
  • It is believed that the charge on a molecule plays a significant role in determining which Lewis structure for a specific molecule is the least energy configuration, among a variety of possible structures. For this reason, the formal charge must be calculated to arrive at the right decision.
  • An important aspect of identifying the primary product of a reaction is determining the lowest energy structure of the reaction. Information such as this can also be extremely helpful in describing a variety of reactions.
  • It has been determined that as a rule of thumb, the structure with the lowest energy is the one that has minimal formal charge and which is the most evenly distributed in real charge.

We now know what a formal charge is, as well as its significance.

Formal Charge VS Oxidation State

  • People sometimes confuse the terms formal charge and oxidation state, as it is often the case that they confuse the two concepts. There is a parallel between these concepts in that both are concerned with the distribution of electrons, however, the viewpoints are very different, and therefore the results are also very different.
  • This subtle difference must be taken into account to remain conscious of these concepts while at the same time being aware of their interrelationship. To calculate the formal charge for a bond, it is assumed that electrons present in the two atoms of the bond are equally distributed between them.
  • With the concept we just discussed, and the subsequent formula that is derived from it, we know that we have a value, which is commonly referred to as the formal charge. When it comes to the oxidation state, however, it is essential to take into account the different electronegativity between the two components of the system.
  • By implication, then, the atom that attracts electrons more strongly gains a competitive advantage over the bond that attracts electrons with less force. Therefore, these two terms shouldn’t be confused with each other since they are fundamentally different and would not be able to be used interchangeably.

Facts About Formal Charge

  • For a complete and accurate Lewis-Kekulé structure, a formal charge is essential. The same cannot be said for organic chemistry.
  • When compared to other structures, the variation with the least charge is the best.
  • In the present day, the valence bond theory of Slater and the molecular orbital theory of Mulliken lead to a more accurate and widely followed oxidation state theory.

Leave a Reply

Your email address will not be published. Required fields are marked *