Pb4SeS3 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form PbS6 octahedra that share corners with three equivalent Pb(1)S6 octahedra, corners with three equivalent Pb(2)Se3S3 octahedra, edges with three equivalent Pb(2)Se3S3 octahedra, and edges with nine equivalent Pb(1)S6 octahedra. The corner-sharing octahedra are not tilted. In the second Pb site, Pb(2) is bonded to three equivalent Se(1) and three equivalent S(1) atoms to form PbSe3S3 octahedra that share corners with three equivalent Pb(1)S6 octahedra, corners with three equivalent Pb(2)Se3S3 octahedra, edges with three equivalent Pb(1)S6 octahedra, and edges with nine equivalent Pb(2)Se3S3 octahedra. The corner-sharing octahedra are not tilted. Se(1) is bonded to six equivalent Pb(2) atoms to form SePb6 octahedra that share corners with six equivalent S(1)Pb6 octahedra, edges with six equivalent Se(1)Pb6 octahedra, and edges with six equivalent S(1)Pb6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Pb(1) and three equivalent Pb(2) atoms to form SPb6 octahedra that share corners with three equivalent Se(1)Pb6 octahedra, corners with three equivalent S(2)Pb6 octahedra, edges with three equivalent Se(1)Pb6 octahedra, edges with three equivalent S(2)Pb6 octahedra, and edges with six equivalent S(1)Pb6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second S site, S(2) is bonded to six equivalent Pb(1) atoms to form a mixture of edge and corner-sharing SPb6 octahedra. The corner-sharing octahedra are not tilted.
Pb4SeS3 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form PbS6 octahedra that share corners with three equivalent Pb(1)S6 octahedra, corners with three equivalent Pb(2)Se3S3 octahedra, edges with three equivalent Pb(2)Se3S3 octahedra, and edges with nine equivalent Pb(1)S6 octahedra. The corner-sharing octahedra are not tilted. All Pb(1)-S(1) bond lengths are 3.00 Å. All Pb(1)-S(2) bond lengths are 3.00 Å. In the second Pb site, Pb(2) is bonded to three equivalent Se(1) and three equivalent S(1) atoms to form PbSe3S3 octahedra that share corners with three equivalent Pb(1)S6 octahedra, corners with three equivalent Pb(2)Se3S3 octahedra, edges with three equivalent Pb(1)S6 octahedra, and edges with nine equivalent Pb(2)Se3S3 octahedra. The corner-sharing octahedra are not tilted. All Pb(2)-Se(1) bond lengths are 3.07 Å. All Pb(2)-S(1) bond lengths are 2.99 Å. Se(1) is bonded to six equivalent Pb(2) atoms to form SePb6 octahedra that share corners with six equivalent S(1)Pb6 octahedra, edges with six equivalent Se(1)Pb6 octahedra, and edges with six equivalent S(1)Pb6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent S sites. In the first S site, S(1) is bonded to three equivalent Pb(1) and three equivalent Pb(2) atoms to form SPb6 octahedra that share corners with three equivalent Se(1)Pb6 octahedra, corners with three equivalent S(2)Pb6 octahedra, edges with three equivalent Se(1)Pb6 octahedra, edges with three equivalent S(2)Pb6 octahedra, and edges with six equivalent S(1)Pb6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the second S site, S(2) is bonded to six equivalent Pb(1) atoms to form a mixture of edge and corner-sharing SPb6 octahedra. The corner-sharing octahedra are not tilted.