FeCu4PbBiS6 is Aluminum carbonitride-derived structured and crystallizes in the orthorhombic Pmc2_1 space group. Fe(1) is bonded to one S(3), one S(4), and two equivalent S(1) atoms to form FeS4 tetrahedra that share corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Cu(1)PbS4 tetrahedra,  an edgeedge with one Cu(2)S4 tetrahedra, edges with two equivalent Cu(3)S4 tetrahedra, and edges with two equivalent Cu(4)S4 tetrahedra. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Pb(1), one S(1), one S(2), and two equivalent S(5) atoms to form CuPbS4 tetrahedra that share corners with four equivalent Bi(1)S5 square pyramids,  a cornercorner with one Cu(3)S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Cu(1)PbS4 tetrahedra, and corners with two equivalent Cu(4)S4 tetrahedra. In the second Cu site, Cu(2) is bonded to one S(3), one S(4), and two equivalent S(6) atoms to form CuS4 tetrahedra that share corners with two equivalent Bi(1)S5 square pyramids, corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra, corners with four equivalent Cu(3)S4 tetrahedra,  an edgeedge with one Bi(1)S5 square pyramid, and  an edgeedge with one Fe(1)S4 tetrahedra. In the third Cu site, Cu(3) is bonded to one S(1), one S(6), and two equivalent S(3) atoms to form CuS4 tetrahedra that share corners with two equivalent Bi(1)S5 square pyramids,  a cornercorner with one Cu(1)PbS4 tetrahedra,  a cornercorner with one Cu(4)S4 tetrahedra, corners with two equivalent Cu(3)S4 tetrahedra, corners with four equivalent Cu(2)S4 tetrahedra, and edges with two equivalent Fe(1)S4 tetrahedra. In the fourth Cu site, Cu(4) is bonded to one S(1), one S(2), and two equivalent S(4) atoms to form distorted CuS4 tetrahedra that share corners with two equivalent Bi(1)S5 square pyramids,  a cornercorner with one Cu(3)S4 tetrahedra, corners with two equivalent Cu(1)PbS4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra, and edges with two equivalent Fe(1)S4 tetrahedra. Pb(1) is bonded in a 6-coordinate geometry to one Cu(1), one S(6), two equivalent S(3), and two equivalent S(5) atoms. Bi(1) is bonded to one S(5), two equivalent S(2), and two equivalent S(6) atoms to form BiS5 square pyramids that share corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Cu(3)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra, corners with four equivalent Cu(1)PbS4 tetrahedra, edges with two equivalent Bi(1)S5 square pyramids, and  an edgeedge with one Cu(2)S4 tetrahedra. There are six inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Fe(1), one Cu(1), one Cu(3), and one Cu(4) atom. In the second S site, S(2) is bonded to one Cu(1), one Cu(4), and two equivalent Bi(1) atoms to form distorted SCu2Bi2 tetrahedra that share corners with two equivalent S(2)Cu2Bi2 tetrahedra and corners with two equivalent S(4)FeCu3 tetrahedra. In the third S site, S(3) is bonded in a 4-coordinate geometry to one Fe(1), one Cu(2), two equivalent Cu(3), and two equivalent Pb(1) atoms. In the fourth S site, S(4) is bonded to one Fe(1), one Cu(2), and two equivalent Cu(4) atoms to form distorted SFeCu3 tetrahedra that share corners with two equivalent S(2)Cu2Bi2 tetrahedra and corners with two equivalent S(4)FeCu3 tetrahedra. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent Cu(1), two equivalent Pb(1), and one Bi(1) atom. In the sixth S site, S(6) is bonded in a 6-coordinate geometry to one Cu(3), two equivalent Cu(2), one Pb(1), and two equivalent Bi(1) atoms.
FeCu4PbBiS6 is Aluminum carbonitride-derived structured and crystallizes in the orthorhombic Pmc2_1 space group. Fe(1) is bonded to one S(3), one S(4), and two equivalent S(1) atoms to form FeS4 tetrahedra that share corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Cu(1)PbS4 tetrahedra,  an edgeedge with one Cu(2)S4 tetrahedra, edges with two equivalent Cu(3)S4 tetrahedra, and edges with two equivalent Cu(4)S4 tetrahedra. The Fe(1)-S(3) bond length is 2.26 Å. The Fe(1)-S(4) bond length is 2.29 Å. Both Fe(1)-S(1) bond lengths are 2.34 Å. There are four inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one Pb(1), one S(1), one S(2), and two equivalent S(5) atoms to form CuPbS4 tetrahedra that share corners with four equivalent Bi(1)S5 square pyramids,  a cornercorner with one Cu(3)S4 tetrahedra, corners with two equivalent Fe(1)S4 tetrahedra, corners with two equivalent Cu(1)PbS4 tetrahedra, and corners with two equivalent Cu(4)S4 tetrahedra. The Cu(1)-Pb(1) bond length is 3.11 Å. The Cu(1)-S(1) bond length is 2.32 Å. The Cu(1)-S(2) bond length is 2.28 Å. Both Cu(1)-S(5) bond lengths are 2.33 Å. In the second Cu site, Cu(2) is bonded to one S(3), one S(4), and two equivalent S(6) atoms to form CuS4 tetrahedra that share corners with two equivalent Bi(1)S5 square pyramids, corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra, corners with four equivalent Cu(3)S4 tetrahedra,  an edgeedge with one Bi(1)S5 square pyramid, and  an edgeedge with one Fe(1)S4 tetrahedra. The Cu(2)-S(3) bond length is 2.38 Å. The Cu(2)-S(4) bond length is 2.33 Å. Both Cu(2)-S(6) bond lengths are 2.38 Å. In the third Cu site, Cu(3) is bonded to one S(1), one S(6), and two equivalent S(3) atoms to form CuS4 tetrahedra that share corners with two equivalent Bi(1)S5 square pyramids,  a cornercorner with one Cu(1)PbS4 tetrahedra,  a cornercorner with one Cu(4)S4 tetrahedra, corners with two equivalent Cu(3)S4 tetrahedra, corners with four equivalent Cu(2)S4 tetrahedra, and edges with two equivalent Fe(1)S4 tetrahedra. The Cu(3)-S(1) bond length is 2.38 Å. The Cu(3)-S(6) bond length is 2.34 Å. Both Cu(3)-S(3) bond lengths are 2.37 Å. In the fourth Cu site, Cu(4) is bonded to one S(1), one S(2), and two equivalent S(4) atoms to form distorted CuS4 tetrahedra that share corners with two equivalent Bi(1)S5 square pyramids,  a cornercorner with one Cu(3)S4 tetrahedra, corners with two equivalent Cu(1)PbS4 tetrahedra, corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra, and edges with two equivalent Fe(1)S4 tetrahedra. The Cu(4)-S(1) bond length is 2.37 Å. The Cu(4)-S(2) bond length is 2.29 Å. Both Cu(4)-S(4) bond lengths are 2.34 Å. Pb(1) is bonded in a 6-coordinate geometry to one Cu(1), one S(6), two equivalent S(3), and two equivalent S(5) atoms. The Pb(1)-S(6) bond length is 3.06 Å. Both Pb(1)-S(3) bond lengths are 3.05 Å. Both Pb(1)-S(5) bond lengths are 2.99 Å. Bi(1) is bonded to one S(5), two equivalent S(2), and two equivalent S(6) atoms to form BiS5 square pyramids that share corners with two equivalent Cu(2)S4 tetrahedra, corners with two equivalent Cu(3)S4 tetrahedra, corners with two equivalent Cu(4)S4 tetrahedra, corners with four equivalent Cu(1)PbS4 tetrahedra, edges with two equivalent Bi(1)S5 square pyramids, and  an edgeedge with one Cu(2)S4 tetrahedra. The Bi(1)-S(5) bond length is 2.63 Å. Both Bi(1)-S(2) bond lengths are 2.72 Å. Both Bi(1)-S(6) bond lengths are 3.08 Å. There are six inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Fe(1), one Cu(1), one Cu(3), and one Cu(4) atom. In the second S site, S(2) is bonded to one Cu(1), one Cu(4), and two equivalent Bi(1) atoms to form distorted SCu2Bi2 tetrahedra that share corners with two equivalent S(2)Cu2Bi2 tetrahedra and corners with two equivalent S(4)FeCu3 tetrahedra. In the third S site, S(3) is bonded in a 4-coordinate geometry to one Fe(1), one Cu(2), two equivalent Cu(3), and two equivalent Pb(1) atoms. In the fourth S site, S(4) is bonded to one Fe(1), one Cu(2), and two equivalent Cu(4) atoms to form distorted SFeCu3 tetrahedra that share corners with two equivalent S(2)Cu2Bi2 tetrahedra and corners with two equivalent S(4)FeCu3 tetrahedra. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent Cu(1), two equivalent Pb(1), and one Bi(1) atom. In the sixth S site, S(6) is bonded in a 6-coordinate geometry to one Cu(3), two equivalent Cu(2), one Pb(1), and two equivalent Bi(1) atoms.