Sigma & Pi bonds

(Polar molecules, Non-polar molecules, etc.)

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Jessica Esparza 2H
Posts: 130
Joined: Wed Sep 18, 2019 12:15 am

Sigma & Pi bonds

Postby Jessica Esparza 2H » Tue Nov 19, 2019 5:23 pm

Sigma bonds can rotate while Pi bonds cant. What gives each this characteristic?

Mashkinadze_1D
Posts: 87
Joined: Sat Aug 24, 2019 12:15 am

Re: Sigma & Pi bonds

Postby Mashkinadze_1D » Tue Nov 19, 2019 5:25 pm

The method through which they are bonded in the s or p suborbitals gives this characteristic. When we look at a sigma bond, we see that it does not have to be fixed in place as it is to the side of the atom, while the pi bonds are above and below a atom and therefore cannot move or they will break. If you remember the manner through which Doctor Lavelle explained this using the pencils and his hands, I believe this helped me understand this the most.

Khushboo_3D
Posts: 60
Joined: Wed Sep 18, 2019 12:19 am

Re: Sigma & Pi bonds

Postby Khushboo_3D » Tue Nov 19, 2019 6:27 pm

The main reason is because sigma bonds are formed when orbitals overlap end-to-end and pi bonds are formed when orbitals overlap side- by -side. This therefore, makes it difficult for pi bonds to rotate since they would break if rotated.

Aprice_1J
Posts: 55
Joined: Wed Sep 18, 2019 12:16 am

Re: Sigma & Pi bonds

Postby Aprice_1J » Tue Nov 19, 2019 9:50 pm

Can anyone explain why double bonds are sigma plus pi and not just pi bonds? If a pi bond represents a double bond why is there a simga bond as well?

Aprice_1J
Posts: 55
Joined: Wed Sep 18, 2019 12:16 am

Re: Sigma & Pi bonds

Postby Aprice_1J » Tue Nov 19, 2019 9:58 pm

Can anyone explain why double bonds are sigma plus pi and not just pi bonds? If a pi bond represents a double bond why is there a simga bond as well?

Subashni Rajiv 1K
Posts: 101
Joined: Wed Sep 18, 2019 12:16 am

Re: Sigma & Pi bonds

Postby Subashni Rajiv 1K » Tue Nov 19, 2019 10:19 pm

It's much lower energy to combine a single sigma bond and a single pi bond than trying to force two sigma bonds between two atoms.


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