Does a resonance structure have more than one Lewis formula?
1 Answer
Each resonance structure only corresponds to one chemical formula... but a single resonance structure has a fixed structure by definition of it being a snapshot of a molecular electronic configuration.
The one chemical formula can have more than one resonance structure, and typically, a stable molecule will have more than one resonance structure.
Take nitrate anion for example...
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Each resonance structure corresponds to only one chemical structure, and that's the one you see on the page. In this case we just have three degenerate structures; if you rotate the first one
But that is no coincidence. This rotational symmetry is what then sensibly gives the resonance hybrid structure, which has 3-fold rotational symmetry axis through the page:
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