Bond rotations

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Kellylin_4D
Posts: 66
Joined: Sat Aug 24, 2019 12:17 am

Bond rotations

Postby Kellylin_4D » Tue Dec 03, 2019 11:38 am

If single bonds can rotate, and double bonds can’t rotate, do resonance rotate?

Sahil Jog 1F
Posts: 126
Joined: Thu Jul 11, 2019 12:16 am

Re: Bond rotations

Postby Sahil Jog 1F » Tue Dec 03, 2019 12:01 pm

I would assume that resonance structures would not rotate, since their electrons are still delocalized throughout the molecule, which expresses a similar 3 dimensional structure as a double bond (1 sigma and 1 pi bond), and thus not allowing for rotation.

605208780
Posts: 50
Joined: Wed Sep 18, 2019 12:16 am

Re: Bond rotations

Postby 605208780 » Tue Dec 03, 2019 12:02 pm

When one or more lewis diagram can be drawn, the molecule is said to have resonance. Resonance isn't about the rotation of bonds, but about the delocalization of electrons that contribute to the overall structure. The idea that resonances rotate isn't really valid.

Blake Ballew 1H
Posts: 85
Joined: Wed Sep 30, 2020 9:35 pm

Re: Bond rotations

Postby Blake Ballew 1H » Sun Nov 29, 2020 10:36 am

What exactly makes single bonds capable of rotation and double bonds unable to do so?

keely_bales_1f
Posts: 89
Joined: Wed Sep 30, 2020 9:41 pm

Re: Bond rotations

Postby keely_bales_1f » Sun Nov 29, 2020 10:48 am

Blake Ballew 1E wrote:What exactly makes single bonds capable of rotation and double bonds unable to do so?


I definitely would rewatch Lavelle's Week 7 Friday Lecture (11/20/20). He draws out sigma and pi bonds and does a demonstration with a pencil that explains why double bonds are incapable of rotating. I have attached my notes of this part of the lecture below if you don't have the time to rewatch Lavelle's lecture. However I highly recommend rewatching this part of the lecture because Lavelle does a great job explaining it in a way that helps you visualize what is happening. Hope this helps you!
Attachments
IMG_0135.jpg

Nina Tartibi 1F
Posts: 52
Joined: Wed Sep 30, 2020 9:58 pm

Re: Bond rotations

Postby Nina Tartibi 1F » Mon Dec 07, 2020 12:46 am

I don't believe that resonance structures would rotate, because there is still a delocalized electron that makes the double bond in resonance structures. Therefore, with that pi-bond in the double bond, it would restrict the molecule from rotating.

Inderpal Singh 2L
Posts: 140
Joined: Wed Sep 30, 2020 10:02 pm
Been upvoted: 2 times

Re: Bond rotations

Postby Inderpal Singh 2L » Mon Dec 07, 2020 3:27 pm

I don't believe that resonant bonds can rotate.

205323697
Posts: 50
Joined: Tue Feb 25, 2020 12:15 am

Re: Bond rotations

Postby 205323697 » Thu Dec 17, 2020 9:52 am

Isnt this why we draw a circle in Benzene?


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