Pb2SeS is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to four equivalent Se(1) and two equivalent S(1) atoms to form PbSe4S2 octahedra that share corners with six equivalent Pb(1)Se4S2 octahedra, edges with four equivalent Pb(1)Se4S2 octahedra, and edges with eight equivalent Pb(2)Se2S4 octahedra. The corner-sharing octahedra are not tilted. In the second Pb site, Pb(2) is bonded to two equivalent Se(1) and four equivalent S(1) atoms to form PbSe2S4 octahedra that share corners with six equivalent Pb(2)Se2S4 octahedra, edges with four equivalent Pb(2)Se2S4 octahedra, and edges with eight equivalent Pb(1)Se4S2 octahedra. The corner-sharing octahedra are not tilted. Se(1) is bonded to two equivalent Pb(2) and four equivalent Pb(1) atoms to form SePb6 octahedra that share corners with six equivalent Se(1)Pb6 octahedra, edges with four equivalent Se(1)Pb6 octahedra, and edges with eight equivalent S(1)Pb6 octahedra. The corner-sharing octahedra are not tilted. S(1) is bonded to two equivalent Pb(1) and four equivalent Pb(2) atoms to form SPb6 octahedra that share corners with six equivalent S(1)Pb6 octahedra, edges with four equivalent S(1)Pb6 octahedra, and edges with eight equivalent Se(1)Pb6 octahedra. The corner-sharing octahedra are not tilted.
Pb2SeS is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to four equivalent Se(1) and two equivalent S(1) atoms to form PbSe4S2 octahedra that share corners with six equivalent Pb(1)Se4S2 octahedra, edges with four equivalent Pb(1)Se4S2 octahedra, and edges with eight equivalent Pb(2)Se2S4 octahedra. The corner-sharing octahedra are not tilted. All Pb(1)-Se(1) bond lengths are 3.04 Å. Both Pb(1)-S(1) bond lengths are 3.05 Å. In the second Pb site, Pb(2) is bonded to two equivalent Se(1) and four equivalent S(1) atoms to form PbSe2S4 octahedra that share corners with six equivalent Pb(2)Se2S4 octahedra, edges with four equivalent Pb(2)Se2S4 octahedra, and edges with eight equivalent Pb(1)Se4S2 octahedra. The corner-sharing octahedra are not tilted. Both Pb(2)-Se(1) bond lengths are 3.05 Å. All Pb(2)-S(1) bond lengths are 3.04 Å. Se(1) is bonded to two equivalent Pb(2) and four equivalent Pb(1) atoms to form SePb6 octahedra that share corners with six equivalent Se(1)Pb6 octahedra, edges with four equivalent Se(1)Pb6 octahedra, and edges with eight equivalent S(1)Pb6 octahedra. The corner-sharing octahedra are not tilted. S(1) is bonded to two equivalent Pb(1) and four equivalent Pb(2) atoms to form SPb6 octahedra that share corners with six equivalent S(1)Pb6 octahedra, edges with four equivalent S(1)Pb6 octahedra, and edges with eight equivalent Se(1)Pb6 octahedra. The corner-sharing octahedra are not tilted.