Partial vs Formal charge

[Mari Williams 1K]

Can someone explain the conceptual difference between partial and formal charges?

[ALee_1J]

Found this post in a previous year:

A formal charge has a value of either a positive integer, a negative integer, or zero. A partial charge usually has a positive or negative non-integer. Each atom in a molecule has both, but in this course, we're only able to calculate the formal charge. For the partial charge, we would use or . To know which atom has a positive or negative partial charge in a bond, we need to compare the electronegativity of both atoms in a bond. For example, for a HO bond, O would have a negative partial charge since it has a higher electronegativity (more to the right side of the periodic table) and H would have a positive partial charge. The electron shared between H and O would be more attracted to O than H since O has a negative partial charge.

A formal charge indicates gain or loss of electron(s) while forming covalent bond(s) (from the course reader). A partial charge indicates which atom in a bond have a higher electronegativity and which have a lower electronegativity.

There's not much of a need to differentiate them since they're already completely different from each other in terms of writing them. After calculating formal charge, you can just say FC (-O) = 0 or something similar to that. If the question asks to the partial charges of a HO bond, you can say - , or if it asks for the partial charge for O in a HO bond, you can just say or .

If I forgot anything or if my explanations are unclear/incomplete, feel free to add on or fix any of my mistakes!

[SashaAnand2J]

Partial charges are usually referred to as dipoles! This is what we are referring to when discussing dipole-ion/dipole-dipole interactions. Partial charges indicate which atom has the electrons closest or furthest away (remember electronegativity!), giving those atoms similar properties as an ion with that charge. Formal charges indicate when a particular atom has a certain amount of electrons, rather than just a negative or positive dipole.

[Alex Benson]

Hi! I believe a formal charge usually refers to a full charge represented by a integer. However a partial charge is usually referred to as a dipole which give the molecule non-uniform distributions of charges.

[Anastasia Yulo 1C]

The formal charge is the charge that an atom appears to have when we count the electrons according to certain arbitrary rules. Formal charge is an integer property that is essential for the correct valence representation of a molecule.

The partial charge is the charge that the atom really has.

[SahajDole_1C]

Partial charges tend to be dipoles and formal charges are the charges on an atom

[Liam Bertrand 3]

To add on to what everyone else said, partial charges are less intense (why they're called partial), can generally fluctuate a bit as the electrons move around, and sometimes only occur at specific moments. A formal charge will not change because it refers to the total number of electrons, and is not dependent on where the electrons are located like a partial charge is.

[LeahSWM 2E]

A partial charge is indicated by which atom of a bond has the higher EN and which has the lower EN. A formal charge is indicated by the # gained or lossed electrons.

[Anastasia Yulo 1C]

The formal charge of an atom indicates the gain or loss of an electron while forming a covalent bond. To determine the formal charge I use the following rationale: Formal Charge = Valence electrons of neutral atom - (Shared electrons/2 - lone pair electrons)