## sigma/pi bonds

$sp, sp^{2}, sp^{3}, dsp^{3}, d^{2}sp^{3}$

Alyssa Bryan 3F
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### sigma/pi bonds

Besides that a single bond = 1 sigma bond, a double bond = 1 sigma + 1 pi bond, and a triple bond = 1 sigma + 2 pi bonds, what else is important about these types of bonds? What is the concept behind them?

marisaimbroane1J
Posts: 69
Joined: Fri Sep 28, 2018 12:23 am

### Re: sigma/pi bonds

It's important to know that when there is a pi bond, the atoms cannot rotate and are left in a single plane. If the atoms were to rotate and change the shape, the pi bond would break and it would be a chemical reaction.

Julia Lee
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Joined: Fri Sep 28, 2018 12:29 am

### Re: sigma/pi bonds

Sigma bonds have an end-to-end interaction allowing bound atoms to rotate. They are always the first bond formed in a molecule and are the strongest bond due to the max amount of overlap.
Pi bonds have a side-by-side interaction and do not allow bound atoms to rotate. They have e- density on each side of the axis and are weaker than sigma bonds. They are the second and third bond formed after the sigma bond.

Parth Mungra
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### Re: sigma/pi bonds

How are pi bonds weaker if they are double/triple bonds? If they hold atoms side by side, doesn't that mean they are stronger since they cannot rotate?

Posts: 32
Joined: Fri Sep 28, 2018 12:23 am

### Re: sigma/pi bonds

Atoms in sigma bonds can rotate and also overlap, whereas atoms in pi bonds can not rotate around the internuclear axis and are only end to end.

705137650
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Joined: Fri Sep 28, 2018 12:18 am

### Re: sigma/pi bonds

Sigma bonds (σ) are the strongest type of covalent bond, formed by head-on overlapping of atomic orbitals. ... Note that every single bond consists of one sigma bond, and that the double bond is made of one sigma bond and one pi bond. Likewise, a triple bond consists of one sigma bond and two pi bonds.

Jackie Ngo 1C
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Joined: Fri Sep 29, 2017 7:06 am

### Re: sigma/pi bonds

If you went to Lavelle's lectures, you'd know that he made the pi bond and sigma bond analogy with his fingers -- if you put both your index fingers up and parallel to each other, that represents a pi bond, which is a bond that cannot rotate, whereas if you put the end of your index fingers together, that represents what a sigma bond is like, and in sigma bonds, you can rotate your hand around. That's the main difference and importance between sigma and pi bonds

Rami_Z_AbuQubo_2K
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Joined: Thu Jun 07, 2018 3:00 am

### Re: sigma/pi bonds

What do you mean by "end to end" or "side to side"?