Following the same general idea, several different researchers have combined effective charges with covalent or ionic radii in different semi-empirical estimates of the electronegativity of atoms. In this context, Pendás and coworkers, following the works by Boyd et al., have shown that a correlation exists between QTAIM-determined ionic radii in alkali halides crystals and tabulated Pauling electronegativity of atoms. Komorowski have formulated electronegativity in terms of a bonding potential term that can be approximated in different ways for ionic and covalent solids. Van Genechten and coworkers 23 evaluated the average electronegativity of atoms inside crystals by calculating the corrective terms for the Mortier-Gosh-Shankar effective electronegativity in solid-state systems with ab-initio methods. An alternative route of atomic partitioning is the one explored by Tachibana, who used energy densities, and particularly, the kinetic energy density to study chemical reactions and shapes of atoms in the real space. Central to our approach for quantifying atomic volume, charge and electronegativity in molecules is a topological analysis of the electron energy density, 𝛸(𝒓). The electron energy density is a product of the electron density 𝜌(𝒓) and a field representing the average electron potential, which we refer to as the average electron energy, 𝜒̅ (𝒓), 𝛸(𝒓) = 𝜒̅ (𝒓)𝜌(𝒓).