Solid state phase transition in Zn3As2

Static vapour-pressure investigation of the three-phase equilibrium S($\text{α}$-Zn_$\text{3}$As_$\text{2}$)S($\text{β}$-Zn_$\text{3}$As_$\text{2}$)V is reported, which describes the $\text{α-β}$ phase transition in Zn_$\text{3}$As_$\text{2}$ at the vapour pressure of the system. Isothermal sections of the P-T-X phase transition region are presented. Temperature and composition ranges of the $\text{α-β}$ transformation are found to be within 0,01 at·% and 937–948 K. Two pressure minima are experimentally registered in the phase transition range. The $\text{α-β}$ transition is shown to be of incongruent type.