Formal Charge (FC)Chemistry

Lewis Structure Formal Charge (FC) & Resonance Stability Calculator

Calculate formal charge (FC) for individual atoms in molecular Lewis structures and polyatomic ions to identify preferred resonance contributors.

Calculated Result

Formal Charge (FC)

0-

Calculator Inputs

e⁻
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e⁻
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e⁻
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Formal Charge (FC)

0-

Number of Attached Covalent Bonds

2 bonds

Number of Lone Pairs

2 pairs

Optimal Zero Formal Charge (FC = 0): Indicates maximum thermodynamic stability and preferred Lewis structure resonance contributor.

Lewis Structure Formal Charge Breakdown

Formal Charge FC
0 -(0%)

Standard molecular structure and chemical bonding tool for resonance stability analysis.

Calculation Methodology

Formal Charge Equation: FC = V - N - (B / 2). Where V is the number of valence electrons of the isolated neutral atom (e.g., C=4, N=5, O=6), N is the count of non-bonding lone-pair electrons, and B is the count of shared bonding electrons (each covalent bond contributes 2).

Frequently Asked Questions

Structures with the lowest formal charge magnitudes (closest to zero) are most stable; any unavoidable negative formal charges should reside on the most electronegative atoms.

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