“…Unfortunately, enormous discrepancies in trends of H as a function of pressure were found in the literature. As a matter of fact, some theoretical models established for calculating the hardness of materials such as compound crystals with metallic bonding, MB 12 (M = Zr, Hf, Y, Lu) with UB 12 ‐type structure, indium antimonide semiconducting compounds, and cubic zinc‐blende cadmium telluride semiconductor compounds, as well as other approaches correlating the hardness H to the bulk modus B , showed that H increases as pressure is elevated. However, other models based on the Pugh's ratio ( G/B ) showed that H decreases with increasing pressure .…”