Figure shows the range of formation energy (shaded regions) of each native defect under the most favorable chemical potential conditions that maximizes DE n (P-1 in Table ). This is atypical for Zintl phases that are commonly p-type seminconductors. Even under the most favorable chemical potential conditions (P-16 in Table In both, the ordered compounds and the disordered alloy, we find that the low-energy acceptor defects are the cation vacancies (V Cd , V Ba , V Sr ) with V Cd being the lowest among them under most growth conditions. Similarly, V P and P Cd are the low-energy native donor defects that limit p-type doping in the parent compound as well as the alloy. However, there are quantitative differences in the defect chemistry of Ba The decrease in the n-type dopability window could be attributed to the increase in the band gap with increase in Sr -Ba