electron density

If P x y z d x d y d z is the probability of finding an electron in the volume element dx dy dz at the point of a molecular entity with coordinates x , y , z, then P x y z is the electron density at this point. For many purposes (e.g. X-ray scattering, forces on atoms) the system behaves exactly as if the electrons were spread out into a continuously distributed charge. The term has frequently been wrongly applied to negative charge population.
See also: charge density
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1110 (https://doi.org/10.1351/pac199466051077)