Splitting of the Chalcopyrite Polyhedron in an Isothermal Zn–Cd–Ge–As Tetrahedron

— Using available fragmentary experimental data, we have constructed an isothermal subsolidus composition diagram of the Zn 3 As 2 –Cd 3 As 2 –Ge–As system and identified the phases involved in stable equilibria with a chalcopyrite solid solution. A consistent model has been proposed for the splitting of the chalcopyrite phase region into Zn 1 – x Cd x GeAs 2 (0 ≤ x < 1) and Cd 1 – y Zn y GeAs 2 (0 ≤ y