The first and second ionization energies of the element 119: absolute hardness and Mulliken electronegativity for the cation 119+ based on an empirical equation involving absolute hardness

The following empirical equation was derived: U_POT=(−0.494r⁺+122.392)(η⁺+η⁻)−109.514η⁺+1191.694kJmol⁻¹, where r⁺ is the cation radius (pm), η⁺ is the absolute hardness of the cation, and η⁻ is the absolute hardness of the anion. This equation in conjunction with Kapustinskii lattice energy values for element 119 halides was employed to calculate the first and second ionization energies of 4.04 and 20.72eV, respectively; for the monocation 119⁺, r⁺=202.2pm, η⁺=8.34 and η⁺=12.38. Furthermore, the second ionization energy for francium was calculated as 23.80eV.