Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

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alexfwang3g
Posts: 50
Joined: Thu Jul 11, 2019 12:16 am

Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

Postby alexfwang3g » Wed Oct 30, 2019 11:19 pm

I know that double bonds are shorter than single bonds. But in a resonance structure, they're the same length. Why?

sarahsalama2E
Posts: 164
Joined: Fri Aug 30, 2019 12:16 am

Re: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

Postby sarahsalama2E » Wed Oct 30, 2019 11:33 pm

This is because the actual structure is a resonance hybrid where the bonds are all roughly the same length. Also in a real structure, electrons move around as well.

Andrew Liang 1I
Posts: 105
Joined: Fri Aug 30, 2019 12:18 am

Re: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

Postby Andrew Liang 1I » Thu Oct 31, 2019 12:48 am

If in reality the bond length in resonance structure is the same how to people observe that triple bonds are shorter than double bonds and that double bonds are shorter than single bonds?

Jialun Chen 4F
Posts: 108
Joined: Sat Sep 07, 2019 12:16 am

Re: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

Postby Jialun Chen 4F » Thu Oct 31, 2019 1:32 am

It's because the resonance hybrid is the actual representation of the structure, which has the same length. While the "alternatives" have different length in double/single bonds, but those are not actual structures.

Maeve Miller 1A
Posts: 51
Joined: Fri Aug 09, 2019 12:16 am

Re: Why do all of the bonds have the same length regardless of double/single bonds in a resonance structure?

Postby Maeve Miller 1A » Thu Oct 31, 2019 9:51 am

They are all the same length because it is more of a hybridization. In drawing Lewis structures, we draw single and double bonds to simplify things and make them visually clear; in real life, however, bonds do not work this way--they would all be of the same length as Dr. Lavelle talked about during lecture.


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