Miedema’s model revisited: The parameter ϕ∗ϕ∗ for Ti, Zr, and Hf

Failures of Miedema’s model to predict enthalpies of formation for binary Zr-based compounds are attributed to the original choice of the parameter for electronegativity, ϕ∗=3.45ϕ∗=3.45 V, for Zr. By refinement procedures based on (1) ab initio enthalpies of formation, (2) reliable calorimetric data for the compounds, and (3) data for elemental metallic Zr we suggest that ϕ∗=3.62ϕ∗=3.62 V is a reasonable choice. With this refined value, the revised enthalpies of formation for Zr-based compounds obtained by the Miedema model are substantially improved. The procedures applied possibly open up a new avenue for improving the reliability of Miedema’s model by critically assessing the parameter ϕ∗ϕ∗ also for other problematic cases, and without changing the original model.