Understanding sigma and pi bonds?

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Adriana Rangel 1A
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Joined: Fri Sep 29, 2017 7:04 am

Understanding sigma and pi bonds?

Postby Adriana Rangel 1A » Wed Nov 15, 2017 5:04 pm

So I have a general understanding of what a sigma and pi bonds are. Correct me if I am wrong but what I understand so far is:
A sigma bond forms when the electron orbitals from different atoms overlap along the internuclear axis. They are cylindrically symmetrical with no nodal planes containing the internuclear axis.
A pi bond is bond in which the two electrons lie in two lobes, one on each side of the internuclear axis. The two lobes bond side-to-side rather than overlapping. Pi bonds are usually weaker than sigma bonds.

Please add to this any key concepts I missed that I should know about these two types of bonds.

Nicole Jacobs 1C
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Re: Understanding sigma and pi bonds?

Postby Nicole Jacobs 1C » Wed Nov 15, 2017 5:40 pm

another thing to add is that sigma bonds can rotate and pi bonds cannot rotate. if pi bonds rotate, then they will break, causing a chemical reaction

Nancy Dinh 2J
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Re: Understanding sigma and pi bonds?

Postby Nancy Dinh 2J » Wed Nov 15, 2017 6:23 pm

Also, sigma bonds are formed by hybridized orbitals overlapping. Unhybridized orbitals formal pi bonds.

Harrison Wang 1H
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Re: Understanding sigma and pi bonds?

Postby Harrison Wang 1H » Wed Nov 15, 2017 7:06 pm

And because molecules with pi bonds are unable to rotate, all of the atoms within the molecule are located in the same plane

Humza_Khan_2J
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Re: Understanding sigma and pi bonds?

Postby Humza_Khan_2J » Thu Nov 16, 2017 6:01 pm

Another way to think about it is that pi bonds are unhybridized orbitals lying side by side(generally, from my knowledge, two p orbitals).

Abdullah2I
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Re: Understanding sigma and pi bonds?

Postby Abdullah2I » Fri Nov 17, 2017 8:39 am

this whole post is really helpful, thanks

204918982
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Re: Understanding sigma and pi bonds?

Postby 204918982 » Sat Nov 18, 2017 4:56 pm

why can't pi bonds rotate?

905022356
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Joined: Mon Oct 02, 2017 7:19 am

Re: Understanding sigma and pi bonds?

Postby 905022356 » Sat Nov 18, 2017 10:54 pm

Given that pi bonds form above and bellow the internuclear axis, they hold the atoms in place, making it impossible for them to rotate.

I also wanted to add that single bonds are sigma bonds, and triple and double bonds are pi bonds.

Michael Cheng 1C
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Re: Understanding sigma and pi bonds?

Postby Michael Cheng 1C » Sun Nov 19, 2017 9:16 am

Do sigma and pi bonds apply to ligands and coordination compounds?


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