Pb6Bi2S9 crystallizes in the orthorhombic Cmcm space group. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in an L-shaped geometry to two equivalent S(3) atoms. In the second Pb site, Pb(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form PbS6 octahedra that share corners with two equivalent Bi(1)S6 octahedra, corners with four equivalent Pb(3)S6 octahedra, edges with two equivalent Pb(2)S6 octahedra, edges with four equivalent Pb(4)S6 octahedra, and edges with six equivalent Pb(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the third Pb site, Pb(3) is bonded to one S(5), two equivalent S(1), and three equivalent S(2) atoms to form PbS6 octahedra that share corners with two equivalent Pb(2)S6 octahedra, corners with three equivalent Pb(4)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, edges with three equivalent Pb(2)S6 octahedra, edges with three equivalent Pb(4)S6 octahedra, and edges with four equivalent Pb(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. In the fourth Pb site, Pb(4) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(5) atoms to form PbS6 octahedra that share corners with two equivalent Bi(1)S6 octahedra, corners with three equivalent Pb(3)S6 octahedra, edges with two equivalent Pb(2)S6 octahedra, edges with two equivalent Pb(4)S6 octahedra, edges with three equivalent Pb(3)S6 octahedra, and edges with three equivalent Bi(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. Bi(1) is bonded to one S(1), one S(3), two equivalent S(4), and two equivalent S(5) atoms to form BiS6 octahedra that share  a cornercorner with one Pb(2)S6 octahedra,  a cornercorner with one Bi(1)S6 octahedra, corners with two equivalent Pb(4)S6 octahedra, edges with two equivalent Pb(3)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, and edges with three equivalent Pb(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. There are five inequivalent S sites. In the first S site, S(1) is bonded to one Pb(2), two equivalent Pb(3), two equivalent Pb(4), and one Bi(1) atom to form SBiPb5 octahedra that share  a cornercorner with one S(1)BiPb5 octahedra, corners with two equivalent S(2)Pb6 octahedra, corners with two equivalent S(5)Bi2Pb3 square pyramids,  a cornercorner with one S(3)Bi2Pb2 tetrahedra, edges with two equivalent S(1)BiPb5 octahedra, edges with five equivalent S(2)Pb6 octahedra, and edges with three equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°. In the second S site, S(2) is bonded to one Pb(4), two equivalent Pb(2), and three equivalent Pb(3) atoms to form SPb6 octahedra that share corners with two equivalent S(1)BiPb5 octahedra, corners with two equivalent S(2)Pb6 octahedra,  a cornercorner with one S(5)Bi2Pb3 square pyramid, edges with five equivalent S(1)BiPb5 octahedra, edges with five equivalent S(2)Pb6 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°. In the third S site, S(3) is bonded to two equivalent Pb(1) and two equivalent Bi(1) atoms to form SBi2Pb2 tetrahedra that share corners with two equivalent S(1)BiPb5 octahedra, corners with four equivalent S(5)Bi2Pb3 square pyramids, and corners with two equivalent S(3)Bi2Pb2 tetrahedra. The corner-sharing octahedral tilt angles are 4°. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to one Pb(4) and two equivalent Bi(1) atoms. In the fifth S site, S(5) is bonded to one Pb(3), two equivalent Pb(4), and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share  a cornercorner with one S(2)Pb6 octahedra, corners with two equivalent S(1)BiPb5 octahedra, corners with two equivalent S(3)Bi2Pb2 tetrahedra, edges with two equivalent S(2)Pb6 octahedra, edges with three equivalent S(1)BiPb5 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°.
Pb6Bi2S9 crystallizes in the orthorhombic Cmcm space group. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in an L-shaped geometry to two equivalent S(3) atoms. Both Pb(1)-S(3) bond lengths are 2.86 Å. In the second Pb site, Pb(2) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form PbS6 octahedra that share corners with two equivalent Bi(1)S6 octahedra, corners with four equivalent Pb(3)S6 octahedra, edges with two equivalent Pb(2)S6 octahedra, edges with four equivalent Pb(4)S6 octahedra, and edges with six equivalent Pb(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Both Pb(2)-S(1) bond lengths are 3.03 Å. All Pb(2)-S(2) bond lengths are 2.96 Å. In the third Pb site, Pb(3) is bonded to one S(5), two equivalent S(1), and three equivalent S(2) atoms to form PbS6 octahedra that share corners with two equivalent Pb(2)S6 octahedra, corners with three equivalent Pb(4)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, edges with three equivalent Pb(2)S6 octahedra, edges with three equivalent Pb(4)S6 octahedra, and edges with four equivalent Pb(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. The Pb(3)-S(5) bond length is 3.10 Å. Both Pb(3)-S(1) bond lengths are 2.98 Å. All Pb(3)-S(2) bond lengths are 2.96 Å. In the fourth Pb site, Pb(4) is bonded to one S(2), one S(4), two equivalent S(1), and two equivalent S(5) atoms to form PbS6 octahedra that share corners with two equivalent Bi(1)S6 octahedra, corners with three equivalent Pb(3)S6 octahedra, edges with two equivalent Pb(2)S6 octahedra, edges with two equivalent Pb(4)S6 octahedra, edges with three equivalent Pb(3)S6 octahedra, and edges with three equivalent Bi(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 1-3°. The Pb(4)-S(2) bond length is 3.14 Å. The Pb(4)-S(4) bond length is 2.82 Å. Both Pb(4)-S(1) bond lengths are 2.97 Å. Both Pb(4)-S(5) bond lengths are 2.99 Å. Bi(1) is bonded to one S(1), one S(3), two equivalent S(4), and two equivalent S(5) atoms to form BiS6 octahedra that share  a cornercorner with one Pb(2)S6 octahedra,  a cornercorner with one Bi(1)S6 octahedra, corners with two equivalent Pb(4)S6 octahedra, edges with two equivalent Pb(3)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, and edges with three equivalent Pb(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-58°. The Bi(1)-S(1) bond length is 3.00 Å. The Bi(1)-S(3) bond length is 2.76 Å. Both Bi(1)-S(4) bond lengths are 2.81 Å. Both Bi(1)-S(5) bond lengths are 2.92 Å. There are five inequivalent S sites. In the first S site, S(1) is bonded to one Pb(2), two equivalent Pb(3), two equivalent Pb(4), and one Bi(1) atom to form SBiPb5 octahedra that share  a cornercorner with one S(1)BiPb5 octahedra, corners with two equivalent S(2)Pb6 octahedra, corners with two equivalent S(5)Bi2Pb3 square pyramids,  a cornercorner with one S(3)Bi2Pb2 tetrahedra, edges with two equivalent S(1)BiPb5 octahedra, edges with five equivalent S(2)Pb6 octahedra, and edges with three equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°. In the second S site, S(2) is bonded to one Pb(4), two equivalent Pb(2), and three equivalent Pb(3) atoms to form SPb6 octahedra that share corners with two equivalent S(1)BiPb5 octahedra, corners with two equivalent S(2)Pb6 octahedra,  a cornercorner with one S(5)Bi2Pb3 square pyramid, edges with five equivalent S(1)BiPb5 octahedra, edges with five equivalent S(2)Pb6 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°. In the third S site, S(3) is bonded to two equivalent Pb(1) and two equivalent Bi(1) atoms to form SBi2Pb2 tetrahedra that share corners with two equivalent S(1)BiPb5 octahedra, corners with four equivalent S(5)Bi2Pb3 square pyramids, and corners with two equivalent S(3)Bi2Pb2 tetrahedra. The corner-sharing octahedral tilt angles are 4°. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to one Pb(4) and two equivalent Bi(1) atoms. In the fifth S site, S(5) is bonded to one Pb(3), two equivalent Pb(4), and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share  a cornercorner with one S(2)Pb6 octahedra, corners with two equivalent S(1)BiPb5 octahedra, corners with two equivalent S(3)Bi2Pb2 tetrahedra, edges with two equivalent S(2)Pb6 octahedra, edges with three equivalent S(1)BiPb5 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-2°.