Alkyne pi bonds are perpendicular to each other? I thought they were parallel?

[EECStoMed]

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Alkyne pi bonds are perpendicular to each other? How is that so? I thought they were parallel? Can someone please clarify? According to EK 1001, #59, alkyne pi bonds are perpendicular to each other.

 

[mongrel]

I think you're confused between how these bonds are represented in drawing and how they are physically oriented in space. For example, ethyne is usually noted as HC≡CH but the physical location of the pi bonds is shown (in this crappy drawing):

Notice the electron clouds of the pi bonds are oriented perpendicular to each other.

 

[FlowLimited]

Alkyne pi bonds are perpendicular to each other? How is that so? I thought they were parallel? Can someone please clarify? According to EK 1001, #59, alkyne pi bonds are perpendicular to each other.

Well pi bonds are bonds between p-orbitals on adjacent atoms. The p-orbitals are by definition perpendicular to each other, and therefore the two pi bonds in an alkyne are thus perpendicular as well.

Make sense?

 

[EECStoMed]

Does this mean that in an alkyne, the sigma, and 2 pi bonds are all perpendicular to each other? Like an X, Y, Z plane?

 

[FlowLimited]

Does this mean that in an alkyne, the sigma, and 2 pi bonds are all perpendicular to each other? Like an X, Y, Z plane?

Well the sigma bond is in the middle, right on the axis between the atoms, so not exactly.

 

[rcd]

Alkyne pi bonds are perpendicular to each other? How is that so? I thought they were parallel? Can someone please clarify? According to EK 1001, #59, alkyne pi bonds are perpendicular to each other.

Alkene pi bonds are parallel, alkyne pi bonds are perpendicular.

 

[FlowLimited]

Alkene pi bonds are parallel, alkyne pi bonds are perpendicular.

Well alkenes only have one pi bond so they aren't parallel or perpendicular. They're nothing. You can't make a comparison if there's only one.

 

[mcat prep]

Alkene and Alkyne chemistry have not been on the real MCAT in more than 4 years.

At the bottom of the following page is a link which specifies the topics which you are responsible for:

http://www.aamc.org/students/mcat/preparing/bsprep.htm

Good luck!

 

[xucardsfan08]

Just remember the picture of the pi-electrons as 6 balloons all held together at the point. This should help with the visualization.

 

[rcd]

Well alkenes only have one pi bond so they aren't parallel or perpendicular. They're nothing. You can't make a comparison if there's only one.

touche.

 

[rcd]

touche.

I know what I meant, pi orbitals are parallel.