The Vickers hardness (H V ) values of all considered boron pnictides, calculated using four contemporary models , are summarized in Table . For zb-BAs, all models except the empirical Chen-Niu model give hardness values that are in good agreement with the experimental value of 22(3) GPa . For BSb and BBi, there is a significant divergence of H V values calculated by different models (see Table ), and the nature of these divergences indicates that in this case all models except the thermodynamic one can be considered unreliable. Previously, we observed a similar situation for the superhard phases of the B-C-N system . Based on the hardness values calculated using the thermodynamic model, we can conclude that in the BAs -BSb -BBi series, the Vickers hardness decreases from 24 to 15 GPa, with practically no differences observed between zinc-blende and qtz polymorphs. In any case, all considered boron pnictides are hard phases with Vickers hardness exceeding that of cemented tungsten carbide, the conventional hard material.