Molecular orbitals arising from p orbitals
2pσ*
overlap of 2p lying along bond axis
2pσ
2pπ*
overlap of two pairs of 2p perpendicular to bond axis
2pπ
The three p-orbitals have the same shape, each having two lobes with different phase signs.
The orientation of these orbitals differs. Each p orbital is perpendicular to the other two.
The orientation of these orbitals differs. Each p orbital is perpendicular to the other two.
Overlap of three p orbitals on adjacent atoms gives six molecular orbitals.
The shape of these depends on which pair of p orbitals overlaps and whether they are added or subtracted.
σ overlap of p-orbitals on the bond axis gives 2pσ and 2pσ*
Swap your mouse between the 2pσ and 2pσ* images to see the different orientations of the overlapping p orbitals. Also note that on overlap, lobes of the same sign reinforce (green with green), and lobes of opposite sign cancel (blue with green).
Note that in the lower energy orbital (2pσ) there are nodes (breaks) in the electron density at the two nuclei but NOT between them.
Note that in the lower energy orbital (2pσ) there are nodes (breaks) in the electron density at the two nuclei but NOT between them.
π overlap of 2p orbitals perpendicular to the bond axis
Four molecular orbitals (two 2pπ and two 2pπ*) result because there are two p orbitals on each atom perpendicular to the bond axis.
π Molecular orbitals have lobes above and below the bond axis. The π* molecular orbitals have breaks in the lobes of electron density both at and between the atoms.
π Molecular orbitals have lobes above and below the bond axis. The π* molecular orbitals have breaks in the lobes of electron density both at and between the atoms.