Universal scales of electronegativity and ionicity from electron scattering factors.

Electronegativity and ionicity are important but difficult concepts. In this work, we present the universal scale of electronegativity by utilizing electron scattering factors. A mapping of our proposed "scattering electronegativity" with Pauling electronegativity and other electronegativity scales is given. Two new ionicity scales based on electron scattering factors are also proposed and compared with Philips's ionicity and Pauling's ionicity. Although electron scattering factors are based on neutral, free, atomic features, scattering electronegativity and ionicity are able to provide rich charge or bonding information of materials in molecules or solid states. Our newly proposed electronegativity scale satisfies the metalloid band criterion (or Si rule). A new Mg rule and a new concept of critical ionicity gap are proposed, successfully distinguishing between the four-fold and six-fold coordinates in the AB crystals.