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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: bishiw on November 14, 2020, 12:50:15 AM

Title: Why can't we form this resonance?
Post by: bishiw on November 14, 2020, 12:50:15 AM
Why isn't this a viable resonance structure?
Title: Re: Why can't we form this resonance?
Post by: AWK on November 14, 2020, 02:54:45 AM
What is the definition of a mesomeric structure?
Does the structure you draw meet the definition requirements?
Title: Re: Why can't we form this resonance?
Post by: Babcock_Hall on November 14, 2020, 08:40:45 AM
What you drew breaks at least one fundamental principle.
Title: Re: Why can't we form this resonance?
Post by: bishiw on November 14, 2020, 09:46:44 AM
Quote from: Babcock_Hall on November 14, 2020, 08:40:45 AM
What you drew breaks at least one fundamental principle.

Which one? I'm completely lost haha. I also meant to draw an oxygen with a + charge, not -.
Title: Re: Why can't we form this resonance?
Post by: bishiw on November 14, 2020, 10:26:49 AM
Quote from: AWK on November 14, 2020, 02:54:45 AM
What is the definition of a mesomeric structure?
Does the structure you draw meet the definition requirements?

I meant to draw an oxygen with a + charge instead. Is that still incorrect?
Title: Re: Why can't we form this resonance?
Post by: Babcock_Hall on November 14, 2020, 10:33:31 AM
It is not a significant contributor to the overall structure.  I suggest thinking about AWK's response.
Title: Re: Why can't we form this resonance?
Post by: NDW on November 17, 2020, 10:36:54 PM
With the + on the oxygen, your charges are balanced. Given the question, it looks like you are too early in your chemistry study to know that a + on an oxygen and a - on a carbon would be very unstable. It's a good question. When drawing resonance structures, avoid creating point charges and breaking electronegativity rules.

Your revised answer follows the rules, but to a more experience chemist it's a bizzare or "wrong" structure.

http://www.chem.ucalgary.ca/courses/350/Carey5th/Ch01/ch1-7.html