Solid-state electronegativity of atoms: new approaches

Electronegativities (EN) of 65 elements (H to Bi, except lanthanides and noble gases, plus U and Th) in solids were derived from various observed parameters, namely, bond energies in solids, structural geometry, work functions and force constants, yielding a set of internally consistent values. The solid-state electronegativities are generally lower than the conventional (`molecular') values, due to different coordination numbers and electronic structure in a solid versus a molecule; the decrease is stronger for metals than for non-metals, hence binary compounds have a wider EN difference and higher bond polarity (ionicity) in the solid than in the molecular (gaseous) state. Under high pressure, the ENs of metals increase and those of non-metals decrease, the binary solid becomes less polar and can ultimately dissociate into elements.