Sigma and Pi Bonding

[hanna_maillard3B]

Could anyone explain sigma and pi bonding because the way the textbook explains it is very confusing. I don't understand how to distinguish which bonds have a sigma bond and which have a pi bond and what nodal planes have to do with either.

[pamcoronel1H]

A sigma bond is basically when the outermost orbitals of 2 atoms overlap.
A sigma bond has no nodal planes, i.e. the electrons can be found anywhere around the internuclear axis since both orbitals are overlapping each other.



A pi bond is when the outermost orbitals of 2 atoms overlap with each other side-by-side on the internuclear axis. When they overlap side by side, this leaves a gap in the middle in between the orbitals, and so there is a nodal plane in pi bonds where no electrons will ever be found.

[Chloe Likwong 2K]

Sigma bonds: end-to-end overlap and must form before a pi bond
Pi bonds: side-by-side overlap and it cannot exist w/o a sigma bond

To further clarify:

Bonds-
Single: 1 sigma, 0 pi
Double: 1 sigma, 1 pi
Triple: 1 sigma, 2 pi

There are comments in this link that provide more clarification:
viewtopic.php?f=41&t=36851