Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: yomi on July 30, 2011, 01:32:03 PM
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How many possible resonance structures can be drawn for N2O?
The answer of this exercise I did is three, but all the informations I found on the internet is two.
What's the real answer?
I think the problem is this: N-N三O. Does this exist?
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I was able to write the following resonance limit structures:
N-=N+=O;
N三N+-O-.
The third structure seems too odd to me:
N2--N+三O+;
I simply can't stand a double negative charge in a resonance limit structure.
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I agree with that.
But, can this prove that the third one doesn't exist?
It's still possible, right?
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Resonance structures don't really 'exist' as drawn. Resonance structures are contributors to the actual molecule. Meaning that any given molecule for which valid resonance structures can be drawn is actually a hybrid of those resonance structures. The degree to which a given resonance structure contributes to the actual structure depends on the likelihood of that particular resonance structure existing at any given point (or more clearly the stability of that particular resonance structure).
The structure you have drawn with the double negative charge would be highly unstable and so is not likely to contribute very much to the actual structure of the molecule. That doesn't mean the resonance structure is invalid, it's just not significant.
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I got it, thanks!