Pi and sigma bonds

[Indy Bui 1l]

Can someone explain why a a single bond is a sigma and why a double bond has a sigma and a pi bond, and the same for triple bonds? thanks

[sbeall_1C]

Sigma bonds refer to the s-orbital, and occur when two orbitals are overlapping end to end. Sigma bonds have no nodal planes containing the internuclear axis. This is the reason why a single bond contains one sigma bond. A pi bond refers to a p-orbital, and occurs when two orbitals overlap side to side. Pi bonds have a single nodal plane and contain the internuclear axis.

[Naren_Ramesh_4F]

I believe Dr. Lavelle will be going over it in the 11/18 lecture.

[Fatemah Yacoub 1F]

A sigma bond almost always forms first so automatically a multiple bond will have one sigma bond. Since pi bonds overlap side by side that is why they form on multiple bonds. Therefore any multiple bond will have one sigma bond and then either 1 or 2 pi bonds.

[BCaballero_4F]

Because a sigma bond is stronger and more stable so there will be one of these, and pi bonds would come after the sigma bond because they are weaker.