recent computational screening study by Amsler et al. suggests that some of these hypothetical P-rich compounds may have very promising properties for optoelectronic applications. The authors investigated ternary compounds with a X 4 Y 2 Z stoichiometry, where X =Mg, Ca, Sr, Ba; Y =P, As, Sb, Bi; and Z=S, Se, Te. The study included machinelearning prediction of stable stoichiometries, global structure prediction, and detailed DFT calculations of the hypothetical materials that resulted from the first two steps. Three out of four phosphosulfides (Ca 4 P 2 S, Sr 4 P 2 S, and Ba 4 P 2 S) were found to be on the convex stability hull in their lowest-energy structure. Thus, these materials are likely to be synthesizable. All three materials exhibited a direct band gap at the Γ point and high band edge dispersion (i.e., low effective masses). The former is often correlated with a high α, the latter with high μ. Their band gaps were found to decrease when moving down the group. At the PBE level, Ca 4 P 2 S had a band gap of 1.8 eV and Ba 4 P 2 S had a band gap of 1.3 eV. At the HSE level (known to yield more accurate band gaps), the corresponding band gaps were roughly 2.7 eV and 2.0 eV, respectively. These combined features indicate that these newly discovered PSs could be highly interesting for visible light emission, multijunction solar cells, and PEC water splitting applications. Their potential air sensitivity should, however, be investigated.