Chemistry — Formal Charge & Oxidation Number

FC = V - N - \tfrac{1}{2}B

\textstyle\sum FC = \text{molecular charge}

\text{O: } -2 \;\text{(usual)}, \quad \text{H: } +1 \;\text{(usual)}

\textstyle\sum (\text{oxidation numbers}) = \text{charge}