Ba6Fe3Si8C2(O10Cl)3 crystallizes in the trigonal P3m1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 12-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(10), two equivalent O(7), two equivalent O(8), two equivalent O(9), and one Cl(1) atom. In the second Ba site, Ba(2) is bonded in a 12-coordinate geometry to one O(5), one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(4), two equivalent O(8), and two equivalent Cl(1) atoms. Fe(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(8) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Fe(1)O5 square pyramids, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(9), and two equivalent O(8) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O5 square pyramids,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(6) and three equivalent O(10) atoms to form corner-sharing SiO4 tetrahedra. In the third Si site, Si(3) is bonded to one O(10), one O(2), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. In the fourth Si site, Si(4) is bonded to one O(6) and three equivalent O(9) atoms to form corner-sharing SiO4 tetrahedra. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to three equivalent O(7) atoms. In the second C site, C(2) is bonded in a trigonal planar geometry to three equivalent O(4) atoms. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one Fe(1), and one Si(3) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Ba(2), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to three equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Ba(1), two equivalent Ba(2), and one C(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to three equivalent Ba(2) atoms. In the sixth O site, O(6) is bonded in a linear geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one C(1) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one Fe(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1), one Si(1), and one Si(4) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to two equivalent Ba(1), one Si(2), and one Si(3) atom. Cl(1) is bonded in a trigonal non-coplanar geometry to one Ba(1) and two equivalent Ba(2) atoms.
Ba6Fe3Si8C2(O10Cl)3 crystallizes in the trigonal P3m1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 12-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(10), two equivalent O(7), two equivalent O(8), two equivalent O(9), and one Cl(1) atom. The Ba(1)-O(4) bond length is 2.67 Å. Both Ba(1)-O(1) bond lengths are 3.07 Å. Both Ba(1)-O(10) bond lengths are 3.24 Å. Both Ba(1)-O(7) bond lengths are 2.83 Å. Both Ba(1)-O(8) bond lengths are 2.95 Å. Both Ba(1)-O(9) bond lengths are 3.08 Å. The Ba(1)-Cl(1) bond length is 3.10 Å. In the second Ba site, Ba(2) is bonded in a 12-coordinate geometry to one O(5), one O(7), two equivalent O(1), two equivalent O(2), two equivalent O(4), two equivalent O(8), and two equivalent Cl(1) atoms. The Ba(2)-O(5) bond length is 3.37 Å. The Ba(2)-O(7) bond length is 2.93 Å. Both Ba(2)-O(1) bond lengths are 2.83 Å. Both Ba(2)-O(2) bond lengths are 3.21 Å. Both Ba(2)-O(4) bond lengths are 3.08 Å. Both Ba(2)-O(8) bond lengths are 2.82 Å. Both Ba(2)-Cl(1) bond lengths are 3.10 Å. Fe(1) is bonded to one O(3), two equivalent O(1), and two equivalent O(8) atoms to form distorted FeO5 square pyramids that share corners with two equivalent Fe(1)O5 square pyramids, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(3)O4 tetrahedra. The Fe(1)-O(3) bond length is 1.94 Å. Both Fe(1)-O(1) bond lengths are 2.03 Å. Both Fe(1)-O(8) bond lengths are 2.01 Å. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(9), and two equivalent O(8) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O5 square pyramids,  a cornercorner with one Si(3)O4 tetrahedra, and  a cornercorner with one Si(4)O4 tetrahedra. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(9) bond length is 1.70 Å. Both Si(1)-O(8) bond lengths are 1.63 Å. In the second Si site, Si(2) is bonded to one O(6) and three equivalent O(10) atoms to form corner-sharing SiO4 tetrahedra. The Si(2)-O(6) bond length is 1.58 Å. All Si(2)-O(10) bond lengths are 1.65 Å. In the third Si site, Si(3) is bonded to one O(10), one O(2), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O5 square pyramids,  a cornercorner with one Si(1)O4 tetrahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The Si(3)-O(10) bond length is 1.69 Å. The Si(3)-O(2) bond length is 1.66 Å. Both Si(3)-O(1) bond lengths are 1.63 Å. In the fourth Si site, Si(4) is bonded to one O(6) and three equivalent O(9) atoms to form corner-sharing SiO4 tetrahedra. The Si(4)-O(6) bond length is 1.58 Å. All Si(4)-O(9) bond lengths are 1.66 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to three equivalent O(7) atoms. All C(1)-O(7) bond lengths are 1.30 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to three equivalent O(4) atoms. All C(2)-O(4) bond lengths are 1.29 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one Fe(1), and one Si(3) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent Ba(2), one Si(1), and one Si(3) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to three equivalent Fe(1) atoms. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Ba(1), two equivalent Ba(2), and one C(2) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to three equivalent Ba(2) atoms. In the sixth O site, O(6) is bonded in a linear geometry to one Si(2) and one Si(4) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to one Ba(2), two equivalent Ba(1), and one C(1) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one Fe(1), and one Si(1) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1), one Si(1), and one Si(4) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to two equivalent Ba(1), one Si(2), and one Si(3) atom. Cl(1) is bonded in a trigonal non-coplanar geometry to one Ba(1) and two equivalent Ba(2) atoms.