Illustrated Glossary of Organic Chemistry

s orbital: An atomic orbital having a radial distribution of electron density (i.e., it is a spherical orbital). Further characterized as having an angular momentum quantum number (l) = 0.

The 2s atomic orbital of carbon is a sphere. It has one node, a hollow spherical 'eggshell' of zero electron density, partway between the nucleus and the outermost edge of the orbital.


Carbon's 2p_x, 2p_y, and 2p_z orbitals each have two lobes, and each orbital has one node where the orbital is "pinched off" at the nucleus.