formal charge vs oxidation number

[sticky1]

what is the difference between formal charge and oxidation number?

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[sciencebooks]

what is the difference between formal charge and oxidation number?

TPR definitions:

Formal charge: The theoretical charge on an atom in a molecule, calculated by V-1/2B-L, where V is the number of valence electrons, B is the number of bonding electrons, and L is the number of lone pairs

Oxidation number:A fictitious system of measuring electron density and distribution. It is the hypothetical charge that would be present on each atom if a molecule was shattered into its individual constituent atoms with bonding electrons ending up with the atom of the bond having the higher electronegativity.

Now... Beyond that wordy mess... Just consider an example.

Take SF4. None of the elements have a formal charge. However, we know each F has an oxidation state of -1 so S must have an oxidation state of +4.

 

[LoLCareerGoals]

Formal charge: assume perfect sharing of bonding el-ons.
Oxidation #: assume complete non-sharing (more el-neg atom has all the bonded el-ons).

Reality: something between the 2 above.