Pb6Bi2S9 crystallizes in the orthorhombic Cmcm space group. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one S(5), two equivalent S(2), and three equivalent S(1) atoms to form PbS6 octahedra that share corners with two equivalent Pb(3)S6 octahedra, corners with three equivalent Bi(1)S6 octahedra, edges with two equivalent Pb(4)S6 octahedra, edges with three equivalent Pb(3)S6 octahedra, edges with three equivalent Bi(1)S6 octahedra, and edges with four equivalent Pb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. In the second Pb site, Pb(2) is bonded in a distorted L-shaped geometry to two equivalent S(3) and four equivalent S(4) atoms. In the third Pb site, Pb(3) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form PbS6 octahedra that share corners with two equivalent Pb(4)S6 octahedra, corners with four equivalent Pb(1)S6 octahedra, edges with two equivalent Pb(3)S6 octahedra, edges with four equivalent Bi(1)S6 octahedra, and edges with six equivalent Pb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the fourth Pb site, Pb(4) is bonded to one S(2), one S(3), two equivalent S(4), and two equivalent S(5) atoms to form distorted PbS6 octahedra that share  a cornercorner with one Pb(3)S6 octahedra,  a cornercorner with one Pb(4)S6 octahedra, corners with two equivalent Bi(1)S6 octahedra, edges with two equivalent Pb(1)S6 octahedra, edges with two equivalent Pb(4)S6 octahedra, and edges with three equivalent Bi(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-60°. Bi(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(5) atoms to form BiS6 octahedra that share corners with two equivalent Pb(4)S6 octahedra, corners with three equivalent Pb(1)S6 octahedra, edges with two equivalent Pb(3)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, edges with three equivalent Pb(1)S6 octahedra, and edges with three equivalent Pb(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. There are five inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Pb(3), three equivalent Pb(1), and one Bi(1) atom to form SBiPb5 octahedra that share corners with two equivalent S(2)Bi2Pb4 octahedra, corners with two equivalent S(1)BiPb5 octahedra,  a cornercorner with one S(5)Bi2Pb3 square pyramid, edges with five equivalent S(2)Bi2Pb4 octahedra, edges with five equivalent S(1)BiPb5 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the second S site, S(2) is bonded to one Pb(3), one Pb(4), two equivalent Pb(1), and two equivalent Bi(1) atoms to form distorted SBi2Pb4 octahedra that share  a cornercorner with one S(2)Bi2Pb4 octahedra, corners with two equivalent S(1)BiPb5 octahedra, corners with two equivalent S(5)Bi2Pb3 square pyramids,  a cornercorner with one S(3)Pb4 tetrahedra, edges with two equivalent S(2)Bi2Pb4 octahedra, edges with five equivalent S(1)BiPb5 octahedra, and edges with three equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the third S site, S(3) is bonded to two equivalent Pb(2) and two equivalent Pb(4) atoms to form SPb4 tetrahedra that share corners with two equivalent S(2)Bi2Pb4 octahedra, corners with four equivalent S(5)Bi2Pb3 square pyramids, and corners with two equivalent S(3)Pb4 tetrahedra. The corner-sharing octahedral tilt angles are 5°. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Pb(2), two equivalent Pb(4), and one Bi(1) atom. In the fifth S site, S(5) is bonded to one Pb(1), two equivalent Pb(4), and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share  a cornercorner with one S(1)BiPb5 octahedra, corners with two equivalent S(2)Bi2Pb4 octahedra, corners with two equivalent S(3)Pb4 tetrahedra, edges with two equivalent S(1)BiPb5 octahedra, edges with three equivalent S(2)Bi2Pb4 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 3-6°.
Pb6Bi2S9 crystallizes in the orthorhombic Cmcm space group. There are four inequivalent Pb sites. In the first Pb site, Pb(1) is bonded to one S(5), two equivalent S(2), and three equivalent S(1) atoms to form PbS6 octahedra that share corners with two equivalent Pb(3)S6 octahedra, corners with three equivalent Bi(1)S6 octahedra, edges with two equivalent Pb(4)S6 octahedra, edges with three equivalent Pb(3)S6 octahedra, edges with three equivalent Bi(1)S6 octahedra, and edges with four equivalent Pb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-5°. The Pb(1)-S(5) bond length is 2.93 Å. Both Pb(1)-S(2) bond lengths are 3.02 Å. There are two shorter (2.92 Å) and one longer (3.06 Å) Pb(1)-S(1) bond length. In the second Pb site, Pb(2) is bonded in a distorted L-shaped geometry to two equivalent S(3) and four equivalent S(4) atoms. Both Pb(2)-S(3) bond lengths are 2.84 Å. All Pb(2)-S(4) bond lengths are 3.23 Å. In the third Pb site, Pb(3) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form PbS6 octahedra that share corners with two equivalent Pb(4)S6 octahedra, corners with four equivalent Pb(1)S6 octahedra, edges with two equivalent Pb(3)S6 octahedra, edges with four equivalent Bi(1)S6 octahedra, and edges with six equivalent Pb(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. Both Pb(3)-S(2) bond lengths are 2.98 Å. All Pb(3)-S(1) bond lengths are 2.96 Å. In the fourth Pb site, Pb(4) is bonded to one S(2), one S(3), two equivalent S(4), and two equivalent S(5) atoms to form distorted PbS6 octahedra that share  a cornercorner with one Pb(3)S6 octahedra,  a cornercorner with one Pb(4)S6 octahedra, corners with two equivalent Bi(1)S6 octahedra, edges with two equivalent Pb(1)S6 octahedra, edges with two equivalent Pb(4)S6 octahedra, and edges with three equivalent Bi(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-60°. The Pb(4)-S(2) bond length is 3.19 Å. The Pb(4)-S(3) bond length is 2.81 Å. Both Pb(4)-S(4) bond lengths are 2.90 Å. Both Pb(4)-S(5) bond lengths are 3.11 Å. Bi(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(5) atoms to form BiS6 octahedra that share corners with two equivalent Pb(4)S6 octahedra, corners with three equivalent Pb(1)S6 octahedra, edges with two equivalent Pb(3)S6 octahedra, edges with two equivalent Bi(1)S6 octahedra, edges with three equivalent Pb(1)S6 octahedra, and edges with three equivalent Pb(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 0-9°. The Bi(1)-S(1) bond length is 3.09 Å. The Bi(1)-S(4) bond length is 2.68 Å. Both Bi(1)-S(2) bond lengths are 2.90 Å. Both Bi(1)-S(5) bond lengths are 2.82 Å. There are five inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Pb(3), three equivalent Pb(1), and one Bi(1) atom to form SBiPb5 octahedra that share corners with two equivalent S(2)Bi2Pb4 octahedra, corners with two equivalent S(1)BiPb5 octahedra,  a cornercorner with one S(5)Bi2Pb3 square pyramid, edges with five equivalent S(2)Bi2Pb4 octahedra, edges with five equivalent S(1)BiPb5 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the second S site, S(2) is bonded to one Pb(3), one Pb(4), two equivalent Pb(1), and two equivalent Bi(1) atoms to form distorted SBi2Pb4 octahedra that share  a cornercorner with one S(2)Bi2Pb4 octahedra, corners with two equivalent S(1)BiPb5 octahedra, corners with two equivalent S(5)Bi2Pb3 square pyramids,  a cornercorner with one S(3)Pb4 tetrahedra, edges with two equivalent S(2)Bi2Pb4 octahedra, edges with five equivalent S(1)BiPb5 octahedra, and edges with three equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the third S site, S(3) is bonded to two equivalent Pb(2) and two equivalent Pb(4) atoms to form SPb4 tetrahedra that share corners with two equivalent S(2)Bi2Pb4 octahedra, corners with four equivalent S(5)Bi2Pb3 square pyramids, and corners with two equivalent S(3)Pb4 tetrahedra. The corner-sharing octahedral tilt angles are 5°. In the fourth S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Pb(2), two equivalent Pb(4), and one Bi(1) atom. In the fifth S site, S(5) is bonded to one Pb(1), two equivalent Pb(4), and two equivalent Bi(1) atoms to form SBi2Pb3 square pyramids that share  a cornercorner with one S(1)BiPb5 octahedra, corners with two equivalent S(2)Bi2Pb4 octahedra, corners with two equivalent S(3)Pb4 tetrahedra, edges with two equivalent S(1)BiPb5 octahedra, edges with three equivalent S(2)Bi2Pb4 octahedra, and edges with two equivalent S(5)Bi2Pb3 square pyramids. The corner-sharing octahedral tilt angles range from 3-6°.