pi and sigma bonds

[Eunice Lee 1A]

I've been reading everywhere, and I don't think I really understand what pi and sigma bonds are and what the difference between them is. Can someone please explain?

[sonalivij]

Sigma bonds overlap end to end at the internuclear axis and mainly occur when a 2pz and 2pz, 2s and 2pz, or 2s and 2s orbital overlap. Pi bonds are perpendicular to the internuclear axis and overlap side to side and occurs mainly when a 2px and 2py orbital overlap.
The important thing to remember about these bonds is a single bond has one sigma bond, a double bond has one sigma bond and one pi bond, and a triple bond has one sigma bond and two pi bonds.

[Samantha Ito 2E]

A sigma bond is the same in all directions around the long axis of the bond with no nodal planes containing the internuclear axis. A pi bond has a single nodal plane containing the internuclear axis.

[Michelle Fu 1H]

To give a explanation in laymans terms:
SIGMA BOND

1) side to side overlap

2) always present in single bonded molecules.

3) It has low energy and most stability and considered as covalent bond which is property of covalent compounds.

Pi BOND

1)head to head overlapping of orbitals.

2) present in double bonded and triple bonded molecules.

3) Its energy is greater than sigma bond so it is less stable than sigma bond.