Pb4SnTe5 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 Te(1) and three equivalent Te(3) atoms to form PbTe6 octahedra that share corners with three equivalent Pb(2)Te6 octahedra, corners with three equivalent Sn(1)Te6 octahedra, edges with three equivalent Pb(2)Te6 octahedra, edges with three equivalent Sn(1)Te6 octahedra, and edges with six equivalent Pb(1)Te6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Pb site, Pb(2) is bonded to three equivalent Te(2) and three equivalent Te(3) atoms to form a mixture of edge and corner-sharing PbTe6 octahedra. The corner-sharing octahedra are not tilted. Sn(1) is bonded to six equivalent Te(1) atoms to form SnTe6 octahedra that share corners with six equivalent Pb(1)Te6 octahedra, edges with six equivalent Pb(1)Te6 octahedra, and edges with six equivalent Sn(1)Te6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded to three equivalent Pb(1) and three equivalent Sn(1) atoms to form TeSn3Pb3 octahedra that share corners with three equivalent Te(3)Pb6 octahedra, corners with three equivalent Te(1)Sn3Pb3 octahedra, edges with three equivalent Te(3)Pb6 octahedra, and edges with nine equivalent Te(1)Sn3Pb3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Te site, Te(2) is bonded to six equivalent Pb(2) atoms to form a mixture of edge and corner-sharing TePb6 octahedra. The corner-sharing octahedra are not tilted. In the third Te site, Te(3) is bonded to three equivalent Pb(1) and three equivalent Pb(2) atoms to form TePb6 octahedra that share corners with three equivalent Te(2)Pb6 octahedra, corners with three equivalent Te(1)Sn3Pb3 octahedra, edges with three equivalent Te(2)Pb6 octahedra, edges with three equivalent Te(1)Sn3Pb3 octahedra, and edges with six equivalent Te(3)Pb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.
Pb4SnTe5 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 Te(1) and three equivalent Te(3) atoms to form PbTe6 octahedra that share corners with three equivalent Pb(2)Te6 octahedra, corners with three equivalent Sn(1)Te6 octahedra, edges with three equivalent Pb(2)Te6 octahedra, edges with three equivalent Sn(1)Te6 octahedra, and edges with six equivalent Pb(1)Te6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. All Pb(1)-Te(1) bond lengths are 3.30 Å. All Pb(1)-Te(3) bond lengths are 3.28 Å. In the second Pb site, Pb(2) is bonded to three equivalent Te(2) and three equivalent Te(3) atoms to form a mixture of edge and corner-sharing PbTe6 octahedra. The corner-sharing octahedra are not tilted. All Pb(2)-Te(2) bond lengths are 3.28 Å. All Pb(2)-Te(3) bond lengths are 3.28 Å. Sn(1) is bonded to six equivalent Te(1) atoms to form SnTe6 octahedra that share corners with six equivalent Pb(1)Te6 octahedra, edges with six equivalent Pb(1)Te6 octahedra, and edges with six equivalent Sn(1)Te6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Sn(1)-Te(1) bond lengths are 3.25 Å. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded to three equivalent Pb(1) and three equivalent Sn(1) atoms to form TeSn3Pb3 octahedra that share corners with three equivalent Te(3)Pb6 octahedra, corners with three equivalent Te(1)Sn3Pb3 octahedra, edges with three equivalent Te(3)Pb6 octahedra, and edges with nine equivalent Te(1)Sn3Pb3 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second Te site, Te(2) is bonded to six equivalent Pb(2) atoms to form a mixture of edge and corner-sharing TePb6 octahedra. The corner-sharing octahedra are not tilted. In the third Te site, Te(3) is bonded to three equivalent Pb(1) and three equivalent Pb(2) atoms to form TePb6 octahedra that share corners with three equivalent Te(2)Pb6 octahedra, corners with three equivalent Te(1)Sn3Pb3 octahedra, edges with three equivalent Te(2)Pb6 octahedra, edges with three equivalent Te(1)Sn3Pb3 octahedra, and edges with six equivalent Te(3)Pb6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.