Pb3Bi2S6 crystallizes in the monoclinic C2/m space group. There are three inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one S(1), one S(7), two equivalent S(3), and two equivalent S(4) atoms to form PbS6 octahedra that share  a cornercorner with one Pb(1)S6 octahedra,  a cornercorner with one Bi(1)S6 octahedra, corners with two equivalent Bi(2)S6 octahedra, edges with two equivalent Pb(1)S6 octahedra, and edges with five equivalent Bi(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the second Pb site, Pb(2) is bonded to one S(6), two equivalent S(2), and two equivalent S(5) atoms to form PbS5 square pyramids that share corners with four equivalent Bi(1)S6 octahedra, corners with two equivalent Pb(2)S5 square pyramids, edges with three equivalent Bi(1)S6 octahedra, and edges with three equivalent Pb(2)S5 square pyramids. The corner-sharing octahedral tilt angles range from 10-87°. In the third Pb site, Pb(3) is bonded in a 3-coordinate geometry to one S(2) and two equivalent S(1) atoms. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one S(1), one S(5), two equivalent S(2), and two equivalent S(6) atoms to form BiS6 octahedra that share  a cornercorner with one Pb(1)S6 octahedra,  a cornercorner with one Bi(1)S6 octahedra, corners with four equivalent Pb(2)S5 square pyramids, edges with two equivalent Bi(1)S6 octahedra, and edges with three equivalent Pb(2)S5 square pyramids. The corner-sharing octahedral tilt angles range from 0-56°. In the second Bi site, Bi(2) is bonded to one S(4), two equivalent S(7), and three equivalent S(3) atoms to form BiS6 octahedra that share corners with two equivalent Pb(1)S6 octahedra, corners with two equivalent Bi(2)S6 octahedra, edges with five equivalent Pb(1)S6 octahedra, and edges with five equivalent Bi(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. There are seven inequivalent S sites. In the first S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to one Pb(1), two equivalent Pb(3), and one Bi(1) atom. In the second S site, S(2) is bonded to one Pb(3), two equivalent Pb(2), and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share corners with four equivalent S(5)Bi2Pb4 octahedra,  an edgeedge with one S(5)Bi2Pb4 octahedra, and edges with two equivalent S(2)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 4-88°. In the third S site, S(3) is bonded to two equivalent Pb(1) and three equivalent Bi(2) atoms to form SBi3Pb2 square pyramids that share corners with two equivalent S(7)Bi4Pb2 octahedra, edges with three equivalent S(7)Bi4Pb2 octahedra, and edges with four equivalent S(3)Bi3Pb2 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Pb(1) and one Bi(2) atom. In the fifth S site, S(5) is bonded to four equivalent Pb(2) and two equivalent Bi(1) atoms to form SBi2Pb4 octahedra that share corners with eight equivalent S(2)Bi2Pb3 square pyramids, edges with two equivalent S(5)Bi2Pb4 octahedra, and edges with two equivalent S(2)Bi2Pb3 square pyramids. In the sixth S site, S(6) is bonded in a 3-coordinate geometry to one Pb(2) and two equivalent Bi(1) atoms. In the seventh S site, S(7) is bonded to two equivalent Pb(1) and four equivalent Bi(2) atoms to form SBi4Pb2 octahedra that share corners with four equivalent S(3)Bi3Pb2 square pyramids, edges with two equivalent S(7)Bi4Pb2 octahedra, and edges with six equivalent S(3)Bi3Pb2 square pyramids.
Pb3Bi2S6 crystallizes in the monoclinic C2/m space group. There are three inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one S(1), one S(7), two equivalent S(3), and two equivalent S(4) atoms to form PbS6 octahedra that share  a cornercorner with one Pb(1)S6 octahedra,  a cornercorner with one Bi(1)S6 octahedra, corners with two equivalent Bi(2)S6 octahedra, edges with two equivalent Pb(1)S6 octahedra, and edges with five equivalent Bi(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. The Pb(1)-S(1) bond length is 2.89 Å. The Pb(1)-S(7) bond length is 3.09 Å. Both Pb(1)-S(3) bond lengths are 3.11 Å. Both Pb(1)-S(4) bond lengths are 2.84 Å. In the second Pb site, Pb(2) is bonded to one S(6), two equivalent S(2), and two equivalent S(5) atoms to form PbS5 square pyramids that share corners with four equivalent Bi(1)S6 octahedra, corners with two equivalent Pb(2)S5 square pyramids, edges with three equivalent Bi(1)S6 octahedra, and edges with three equivalent Pb(2)S5 square pyramids. The corner-sharing octahedral tilt angles range from 10-87°. The Pb(2)-S(6) bond length is 2.76 Å. Both Pb(2)-S(2) bond lengths are 3.00 Å. Both Pb(2)-S(5) bond lengths are 2.94 Å. In the third Pb site, Pb(3) is bonded in a 3-coordinate geometry to one S(2) and two equivalent S(1) atoms. The Pb(3)-S(2) bond length is 2.99 Å. Both Pb(3)-S(1) bond lengths are 2.83 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one S(1), one S(5), two equivalent S(2), and two equivalent S(6) atoms to form BiS6 octahedra that share  a cornercorner with one Pb(1)S6 octahedra,  a cornercorner with one Bi(1)S6 octahedra, corners with four equivalent Pb(2)S5 square pyramids, edges with two equivalent Bi(1)S6 octahedra, and edges with three equivalent Pb(2)S5 square pyramids. The corner-sharing octahedral tilt angles range from 0-56°. The Bi(1)-S(1) bond length is 2.64 Å. The Bi(1)-S(5) bond length is 3.08 Å. Both Bi(1)-S(2) bond lengths are 2.88 Å. Both Bi(1)-S(6) bond lengths are 2.79 Å. In the second Bi site, Bi(2) is bonded to one S(4), two equivalent S(7), and three equivalent S(3) atoms to form BiS6 octahedra that share corners with two equivalent Pb(1)S6 octahedra, corners with two equivalent Bi(2)S6 octahedra, edges with five equivalent Pb(1)S6 octahedra, and edges with five equivalent Bi(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. The Bi(2)-S(4) bond length is 2.68 Å. Both Bi(2)-S(7) bond lengths are 2.96 Å. There are two shorter (2.75 Å) and one longer (3.06 Å) Bi(2)-S(3) bond length. There are seven inequivalent S sites. In the first S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to one Pb(1), two equivalent Pb(3), and one Bi(1) atom. In the second S site, S(2) is bonded to one Pb(3), two equivalent Pb(2), and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share corners with four equivalent S(5)Bi2Pb4 octahedra,  an edgeedge with one S(5)Bi2Pb4 octahedra, and edges with two equivalent S(2)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 4-88°. In the third S site, S(3) is bonded to two equivalent Pb(1) and three equivalent Bi(2) atoms to form SBi3Pb2 square pyramids that share corners with two equivalent S(7)Bi4Pb2 octahedra, edges with three equivalent S(7)Bi4Pb2 octahedra, and edges with four equivalent S(3)Bi3Pb2 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Pb(1) and one Bi(2) atom. In the fifth S site, S(5) is bonded to four equivalent Pb(2) and two equivalent Bi(1) atoms to form SBi2Pb4 octahedra that share corners with eight equivalent S(2)Bi2Pb3 square pyramids, edges with two equivalent S(5)Bi2Pb4 octahedra, and edges with two equivalent S(2)Bi2Pb3 square pyramids. In the sixth S site, S(6) is bonded in a 3-coordinate geometry to one Pb(2) and two equivalent Bi(1) atoms. In the seventh S site, S(7) is bonded to two equivalent Pb(1) and four equivalent Bi(2) atoms to form SBi4Pb2 octahedra that share corners with four equivalent S(3)Bi3Pb2 square pyramids, edges with two equivalent S(7)Bi4Pb2 octahedra, and edges with six equivalent S(3)Bi3Pb2 square pyramids.