CHEMISTRY COMMUNITY

What would the Formal Charge equation be used for and what does each letter in the equation represent?

We use the formal charge equation to help us find the most stable structure of a molecule.
in FC= V -(L + S/2), V= number of valence electrons, L= number of lone pair electrons, S= number of shared electrons

Formal charge indicates the gain or loss of electrons that occurs when a covalent bond is formed since the electrons are shared in a covalent bond.

We use the formal charge equation to find the most stable electron sharing pattern for a molecule. You want to maximize the number of zero formal charges that you can, but if it is impossible to assign every atom a zero formal charge, then ideally you would put the negative formal charge with the most electronegative atom, and the positive formal charges with the least electronegative atoms. Also, the less the magnitude of the formal charge, the better, for example, a -1 is more stable than -2, and +1 is more stable than +2, etc.

The formal charge of an atom is the measure of redistributed electrons in a Lewis structure. Essentially, it is the charge an atom would have if it shared a perfectly covalent bond with other atoms. To find formal charge, use the equation:

FC=V–(L+S/2),

where V represents the number of valence electrons, L is the number of electrons presented as lone pairs, and S is the number of shared electrons.

A formal charge of 0 is considered most stable and it is essentially another way to figure out how to make a lewis dot structure as you want the element that is more electronegative to have the negative charge and vice versa.