An exemplary case is the comparison of Ag 3 PS 4 and Ba 4 P 2 S (Fig. ). From a chemical standpoint, these two materials are completely different. Ag 3 PS 4 is a 3D thiophosphate featuring the common [PS 4 ] -3 tetrahedral polyanion, no metal-phosphorus bonds, and P in the +5 oxidation state. P states give an appreciable contribution to the conduction band minimum (CBM), which is predominantly of Ag(s) character. The valence band maximum (VBM) consists of hybridized Ag(d)-S(p) orbitals and contains no meaningful contributions from P states. Ba 4 P 2 S is a 3D PS with independent P 3-and S 2-anions and no other bonds than metal-P and metal-S bonds. Opposite to the case of Ag 3 PS 4 , the VBM of Ba 4 P 2 S is dominated by P(p) states as in III-V semiconductors. On the other hand, the CBM in Ba 4 P 2 S is mainly composed of Ba(d) states without substantial contributions from P orbitals. Although sulfur states give important contribution to both band edges in Ag 3 PS 4 , they are virtually absent in Ba 4 P 2 S.