What is Pi bond?
[[Image:Electron orbitals.svg|right|thumb|350px|Electron atomic and molecular orbitals, showing a pi bond at the bottom right of the picture.]] In [[chemistry]], a '''pi bond''' ('''π bond''') is a [[covalent bond|covalent]] [[chemical bond]] where the [[atomic orbital|orbital]] path of one [[electron]] crosses (overlaps) with the path of another. The electrons have a lobe shaped figure of eight path (see picture). There are two areas of overlap as the paths overlap on both lobes. Only one of the orbital's [[nodal plane]]s passes through both of the involved [[atomic nucleus|nuclei]].<ref>{{cite web | url=https://www.vedantu.com/chemistry/difference-between-sigma-and-pi-bond | title=Difference Between Sigma and Pi Bond }}</ref> [[Image:Pi-Bond.svg|thumb|left|Two p-orbitals forming a π-bond.]] The [[Greek alphabet|Greek]] letter '''π''' in their name refers to [[p orbital]]s. The orbital [[symmetry]] of the pi bond looks the same as the p orbital when seen down the bond axis. P orbitals usually have this sort of bonding. D orbitals are also assumed to use pi bonding but this is not necessarily what happens in reality. The idea of bonding d orbitals fits in with the theory of [[hypervalence]]. Pi bonds are usually weaker than [[sigma bond]]s. [[Quantum mechanics]] says this is because the orbital paths are parallel so there is much less overlap between the p-orbitals. Pi bonds happen when two atomic orbitals are in contact through two areas of overlap. Pi-bonds are more spread out bonds than the sigma bonds. Electrons in pi bonds are sometimes called '''pi electrons'''. Molecular fragments joined by a pi bond cannot rotate about that bond without breaking the pi bond. The rotation destroys the parallel paths of the two p orbitals.<ref>{{cite web | url=https://www.britannica.com/science/pi-bond | title=Pi bond &#124; chemistry &#124; Britannica }}</ref> == Multiple bonds == Atoms that are joined by a [[double bond]] have one sigma bond and one pi bond. If they are joined by a [[triple bond]] they have one s