Pi bond

Each of these atomic orbitals has an electron density of zero at a shared nodal plane that passes through the two bonded nuclei.

This latter mode forms part of the basis for metal-metal multiple bonding.

From the perspective of quantum mechanics, this bond's weakness is explained by significantly less overlap between the component p-orbitals due to their parallel orientation.

The corresponding antibonding, or π* ("pi-star") molecular orbital, is defined by the presence of an additional nodal plane between these two bonded atoms.

A pi bond can exist between two atoms that do not have a net sigma-bonding effect between them.

These compounds have been used as computational models for analysis of pi bonding itself, revealing that in order to achieve maximum orbital overlap the bond distances are much shorter than expected.