Question

A pi bond is formed by the overlap of:

Answer 1

There are two types of bonds known to us and they are sigma bonds and pi bonds. Both are covalent bonds which differ in the overlapping of atomic orbitals. Covalent bonds are formed by the overlapping of atomic orbitals. Sigma bonds are formed due to head-to-head overlapping of atomic orbitals and pi bonds are formed due to lateral overlap of two atomic orbitals.

Complete answer:
If we talk about the formation of pi bonds we see that they are formed by the sidewise positive overlap of atomic orbitals and along a direction which is perpendicular to the internuclear axis. When the formation of pi bonds is taking place, the axes of the atomic orbitals become parallel to each other and the overlapping is perpendicular to the internuclear axis. We can also say that when two p orbitals combine with each other they together form a pi bond (p-p overlapping). In this process the electron density is concentrated above and below the plane of the nuclei of the bonding atoms.

Note:
If we talk about the formation of sigma bonds then this bond is formed by the overlap of atomic orbitals in an end-to-end sense, with the electron density concentrated between the nuclei of the bonding atoms. As from the example of pi bond formation, sigma bond is also formed when s-s, s-p or p-p orbital overlap along the internuclear axis. They both are equally important and have great significance in the field of chemistry.