Pb3Bi2S6 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one S(2), two equivalent S(4), and three equivalent S(3) atoms to form PbS6 octahedra that share corners with two equivalent Pb(1)S6 octahedra, corners with two equivalent Bi(1)S6 octahedra, edges with five equivalent Pb(1)S6 octahedra, and edges with five equivalent Bi(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second Pb site, Pb(2) is bonded in a 6-coordinate geometry to two equivalent S(1) and four equivalent S(2) atoms. Bi(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form BiS6 octahedra that share corners with two equivalent Pb(1)S6 octahedra, corners with two equivalent Bi(1)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, and edges with five equivalent Pb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. There are four inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Pb(2) and two equivalent Bi(1) atoms to form SBi2Pb2 tetrahedra that share corners with two equivalent S(4)Bi2Pb4 octahedra, corners with four equivalent S(3)Bi2Pb3 square pyramids, and corners with two equivalent S(1)Bi2Pb2 tetrahedra. The corner-sharing octahedral tilt angles are 6°. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Pb(1), two equivalent Pb(2), and two equivalent Bi(1) atoms. In the third S site, S(3) is bonded to three equivalent Pb(1) and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share corners with two equivalent S(4)Bi2Pb4 octahedra, corners with two equivalent S(1)Bi2Pb2 tetrahedra, edges with three equivalent S(4)Bi2Pb4 octahedra, and edges with four equivalent S(3)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles are 1°. In the fourth S site, S(4) is bonded to four equivalent Pb(1) and two equivalent Bi(1) atoms to form SBi2Pb4 octahedra that share corners with four equivalent S(3)Bi2Pb3 square pyramids, corners with two equivalent S(1)Bi2Pb2 tetrahedra, edges with two equivalent S(4)Bi2Pb4 octahedra, and edges with six equivalent S(3)Bi2Pb3 square pyramids.
Pb3Bi2S6 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one S(2), two equivalent S(4), and three equivalent S(3) atoms to form PbS6 octahedra that share corners with two equivalent Pb(1)S6 octahedra, corners with two equivalent Bi(1)S6 octahedra, edges with five equivalent Pb(1)S6 octahedra, and edges with five equivalent Bi(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Pb(1)-S(2) bond length is 2.82 Å. Both Pb(1)-S(4) bond lengths are 2.95 Å. There are two shorter (2.99 Å) and one longer (3.12 Å) Pb(1)-S(3) bond length. In the second Pb site, Pb(2) is bonded in a 6-coordinate geometry to two equivalent S(1) and four equivalent S(2) atoms. Both Pb(2)-S(1) bond lengths are 2.90 Å. All Pb(2)-S(2) bond lengths are 3.17 Å. Bi(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form BiS6 octahedra that share corners with two equivalent Pb(1)S6 octahedra, corners with two equivalent Bi(1)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, and edges with five equivalent Pb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. The Bi(1)-S(1) bond length is 2.74 Å. The Bi(1)-S(4) bond length is 3.09 Å. Both Bi(1)-S(2) bond lengths are 2.82 Å. Both Bi(1)-S(3) bond lengths are 2.86 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Pb(2) and two equivalent Bi(1) atoms to form SBi2Pb2 tetrahedra that share corners with two equivalent S(4)Bi2Pb4 octahedra, corners with four equivalent S(3)Bi2Pb3 square pyramids, and corners with two equivalent S(1)Bi2Pb2 tetrahedra. The corner-sharing octahedral tilt angles are 6°. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Pb(1), two equivalent Pb(2), and two equivalent Bi(1) atoms. In the third S site, S(3) is bonded to three equivalent Pb(1) and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share corners with two equivalent S(4)Bi2Pb4 octahedra, corners with two equivalent S(1)Bi2Pb2 tetrahedra, edges with three equivalent S(4)Bi2Pb4 octahedra, and edges with four equivalent S(3)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles are 1°. In the fourth S site, S(4) is bonded to four equivalent Pb(1) and two equivalent Bi(1) atoms to form SBi2Pb4 octahedra that share corners with four equivalent S(3)Bi2Pb3 square pyramids, corners with two equivalent S(1)Bi2Pb2 tetrahedra, edges with two equivalent S(4)Bi2Pb4 octahedra, and edges with six equivalent S(3)Bi2Pb3 square pyramids.