using the experimental values of B 0 , B 0 ʹ and V 0 (Table ), and is equal to 117 GPa. Thus, it can be assumed that the pressure-induced phase transition from zb-BAs to qtz BAs can occur at pressures not lower than 117 GPa, which is consistent with the experimental data on the absence of roomtemperature phase transitions of zb-BAs up to 125 GPa .