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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: wynn on May 11, 2012, 05:57:41 PM

Title: The stability of following resonance structures
Post by: wynn on May 11, 2012, 05:57:41 PM
The structure on the left hand side has the positive charge on a tertiary carbon. Normally, I will pick that one as the molecule with more stability; however, although the structure on the right hand side has a positive charge on the oxygen, the oxygen also has an octet. So, which of them is more stable???
Title: Re: The stability of following resonance structures
Post by: Sophia7X on May 11, 2012, 08:02:21 PM
Generally the more stable structure has the less electronegative elements with a positive formal charge, but I think the right structure is better and more significant than the left structure because BOTH the carbon and the oxygen have an octet, while the carbon in the first structure lacks an octet.
Title: Re: The stability of following resonance structures
Post by: Babcock_Hall on May 12, 2012, 10:53:15 AM
One might rephrase your question as "Which of the two resonance forms makes the greater contribution to the true structure?"  I lean toward the one which gives all atoms a full octet, but perhaps a physical organic chemist should have the last word.