Ba6MgCo2(Sb2O9)2 crystallizes in the triclinic P1 space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(15), one O(16), one O(8), one O(9), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(10), one O(11), one O(13), one O(17), one O(5), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In the third Ba site, Ba(3) is bonded in a 4-coordinate geometry to one O(4), one O(6), one O(8), and one O(9) atom. In the fourth Ba site, Ba(4) is bonded to one O(1), one O(14), one O(15), one O(16), one O(2), one O(3), two equivalent O(10), two equivalent O(11), and two equivalent O(5) atoms to form distorted BaO12 cuboctahedra that share corners with six equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Sb(2)O6 octahedra, faces with three equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Co(1)O6 octahedra, faces with three equivalent Sb(3)O6 octahedra, and  a faceface with one Sb(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 5-10°. In the fifth Ba site, Ba(5) is bonded to one O(10), one O(11), one O(4), one O(5), one O(6), one O(7), two equivalent O(14), two equivalent O(15), and two equivalent O(16) atoms to form distorted BaO12 cuboctahedra that share corners with six equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Co(1)O6 octahedra, faces with three equivalent Sb(2)O6 octahedra, and faces with three equivalent Sb(3)O6 octahedra. In the sixth Ba site, Ba(6) is bonded in a 10-coordinate geometry to one O(1), one O(12), one O(2), one O(3), two equivalent O(13), two equivalent O(17), and two equivalent O(18) atoms. Mg(1) is bonded in a distorted see-saw-like geometry to one O(12), one O(17), one O(18), and one O(9) atom. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(10), one O(11), one O(2), one O(3), and one O(5) atom to form CoO6 octahedra that share corners with three equivalent Sb(3)O6 octahedra, corners with three equivalent Sb(1)O5 square pyramids,  a faceface with one Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-14°. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(4), one O(6), one O(7), one O(8), and one O(9) atom. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(1), one O(13), one O(17), one O(2), and one O(3) atom to form SbO5 square pyramids that share corners with three equivalent Co(1)O6 octahedra and  a faceface with one Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 11-22°. In the second Sb site, Sb(2) is bonded to one O(14), one O(15), one O(16), one O(4), one O(6), and one O(7) atom to form SbO6 octahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and  a faceface with one Sb(3)O6 octahedra. In the third Sb site, Sb(3) is bonded to one O(10), one O(11), one O(14), one O(15), one O(16), and one O(5) atom to form SbO6 octahedra that share corners with three equivalent Co(1)O6 octahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and  a faceface with one Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-14°. In the fourth Sb site, Sb(4) is bonded in a 4-coordinate geometry to one O(12), one O(13), one O(18), and one O(8) atom. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(2), one Co(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(2), one Co(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(2), one Co(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Ba(3), one Ba(5), two equivalent Ba(1), one Co(2), and one Sb(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Co(1), and one Sb(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(3), one Ba(5), two equivalent Ba(1), one Co(2), and one Sb(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ba(5), two equivalent Ba(1), one Co(2), and one Sb(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(3), one Co(2), and one Sb(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(3), one Mg(1), and one Co(2) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Co(1), and one Sb(3) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Co(1), and one Sb(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 120 degrees geometry to one Ba(6), one Mg(1), and one Sb(4) atom. In the thirteenth O site, O(13) is bonded to one Ba(2), two equivalent Ba(6), one Sb(1), and one Sb(4) atom to form distorted corner-sharing OBa3Sb2 square pyramids. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to one Ba(4), two equivalent Ba(5), one Sb(2), and one Sb(3) atom. In the fifteenth O site, O(15) is bonded in a distorted L-shaped geometry to one Ba(1), one Ba(4), two equivalent Ba(5), one Sb(2), and one Sb(3) atom. In the sixteenth O site, O(16) is bonded to one Ba(1), one Ba(4), two equivalent Ba(5), one Sb(2), and one Sb(3) atom to form distorted corner-sharing OBa4Sb2 octahedra. The corner-sharing octahedral tilt angles are 7°. In the seventeenth O site, O(17) is bonded in a 2-coordinate geometry to one Ba(2), two equivalent Ba(6), one Mg(1), and one Sb(1) atom. In the eighteenth O site, O(18) is bonded in a 2-coordinate geometry to two equivalent Ba(6), one Mg(1), and one Sb(4) atom.
Ba6MgCo2(Sb2O9)2 crystallizes in the triclinic P1 space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 10-coordinate geometry to one O(15), one O(16), one O(8), one O(9), two equivalent O(4), two equivalent O(6), and two equivalent O(7) atoms. The Ba(1)-O(15) bond length is 3.24 Å. The Ba(1)-O(16) bond length is 3.24 Å. The Ba(1)-O(8) bond length is 2.80 Å. The Ba(1)-O(9) bond length is 2.72 Å. There is one shorter (2.90 Å) and one longer (3.04 Å) Ba(1)-O(4) bond length. There is one shorter (2.86 Å) and one longer (3.14 Å) Ba(1)-O(6) bond length. There is one shorter (2.98 Å) and one longer (3.02 Å) Ba(1)-O(7) bond length. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(10), one O(11), one O(13), one O(17), one O(5), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Ba(2)-O(10) bond length is 2.83 Å. The Ba(2)-O(11) bond length is 3.21 Å. The Ba(2)-O(13) bond length is 2.82 Å. The Ba(2)-O(17) bond length is 2.95 Å. The Ba(2)-O(5) bond length is 3.01 Å. There is one shorter (2.78 Å) and one longer (3.21 Å) Ba(2)-O(1) bond length. There is one shorter (2.81 Å) and one longer (3.15 Å) Ba(2)-O(2) bond length. There is one shorter (2.96 Å) and one longer (3.00 Å) Ba(2)-O(3) bond length. In the third Ba site, Ba(3) is bonded in a 4-coordinate geometry to one O(4), one O(6), one O(8), and one O(9) atom. The Ba(3)-O(4) bond length is 2.85 Å. The Ba(3)-O(6) bond length is 2.70 Å. The Ba(3)-O(8) bond length is 2.66 Å. The Ba(3)-O(9) bond length is 2.84 Å. In the fourth Ba site, Ba(4) is bonded to one O(1), one O(14), one O(15), one O(16), one O(2), one O(3), two equivalent O(10), two equivalent O(11), and two equivalent O(5) atoms to form distorted BaO12 cuboctahedra that share corners with six equivalent Ba(4)O12 cuboctahedra, corners with three equivalent Sb(2)O6 octahedra, faces with three equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Co(1)O6 octahedra, faces with three equivalent Sb(3)O6 octahedra, and  a faceface with one Sb(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 5-10°. The Ba(4)-O(1) bond length is 3.32 Å. The Ba(4)-O(14) bond length is 2.90 Å. The Ba(4)-O(15) bond length is 3.08 Å. The Ba(4)-O(16) bond length is 3.03 Å. The Ba(4)-O(2) bond length is 3.21 Å. The Ba(4)-O(3) bond length is 2.85 Å. There is one shorter (2.91 Å) and one longer (3.05 Å) Ba(4)-O(10) bond length. There is one shorter (2.90 Å) and one longer (3.09 Å) Ba(4)-O(11) bond length. There is one shorter (2.89 Å) and one longer (3.06 Å) Ba(4)-O(5) bond length. In the fifth Ba site, Ba(5) is bonded to one O(10), one O(11), one O(4), one O(5), one O(6), one O(7), two equivalent O(14), two equivalent O(15), and two equivalent O(16) atoms to form distorted BaO12 cuboctahedra that share corners with six equivalent Ba(5)O12 cuboctahedra, faces with three equivalent Ba(4)O12 cuboctahedra,  a faceface with one Co(1)O6 octahedra, faces with three equivalent Sb(2)O6 octahedra, and faces with three equivalent Sb(3)O6 octahedra. The Ba(5)-O(10) bond length is 3.27 Å. The Ba(5)-O(11) bond length is 2.88 Å. The Ba(5)-O(4) bond length is 3.03 Å. The Ba(5)-O(5) bond length is 3.05 Å. The Ba(5)-O(6) bond length is 3.10 Å. The Ba(5)-O(7) bond length is 2.79 Å. There is one shorter (2.93 Å) and one longer (3.08 Å) Ba(5)-O(14) bond length. There is one shorter (2.96 Å) and one longer (2.98 Å) Ba(5)-O(15) bond length. There is one shorter (2.96 Å) and one longer (3.00 Å) Ba(5)-O(16) bond length. In the sixth Ba site, Ba(6) is bonded in a 10-coordinate geometry to one O(1), one O(12), one O(2), one O(3), two equivalent O(13), two equivalent O(17), and two equivalent O(18) atoms. The Ba(6)-O(1) bond length is 2.74 Å. The Ba(6)-O(12) bond length is 2.97 Å. The Ba(6)-O(2) bond length is 2.68 Å. The Ba(6)-O(3) bond length is 3.20 Å. There is one shorter (2.88 Å) and one longer (3.09 Å) Ba(6)-O(13) bond length. There is one shorter (2.84 Å) and one longer (3.15 Å) Ba(6)-O(17) bond length. There is one shorter (2.90 Å) and one longer (3.52 Å) Ba(6)-O(18) bond length. Mg(1) is bonded in a distorted see-saw-like geometry to one O(12), one O(17), one O(18), and one O(9) atom. The Mg(1)-O(12) bond length is 2.05 Å. The Mg(1)-O(17) bond length is 2.14 Å. The Mg(1)-O(18) bond length is 2.07 Å. The Mg(1)-O(9) bond length is 2.05 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(1), one O(10), one O(11), one O(2), one O(3), and one O(5) atom to form CoO6 octahedra that share corners with three equivalent Sb(3)O6 octahedra, corners with three equivalent Sb(1)O5 square pyramids,  a faceface with one Ba(5)O12 cuboctahedra, and faces with three equivalent Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 7-14°. The Co(1)-O(1) bond length is 2.16 Å. The Co(1)-O(10) bond length is 2.16 Å. The Co(1)-O(11) bond length is 2.11 Å. The Co(1)-O(2) bond length is 2.34 Å. The Co(1)-O(3) bond length is 2.10 Å. The Co(1)-O(5) bond length is 2.11 Å. In the second Co site, Co(2) is bonded in a 5-coordinate geometry to one O(4), one O(6), one O(7), one O(8), and one O(9) atom. The Co(2)-O(4) bond length is 2.61 Å. The Co(2)-O(6) bond length is 2.08 Å. The Co(2)-O(7) bond length is 2.07 Å. The Co(2)-O(8) bond length is 1.93 Å. The Co(2)-O(9) bond length is 1.96 Å. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(1), one O(13), one O(17), one O(2), and one O(3) atom to form SbO5 square pyramids that share corners with three equivalent Co(1)O6 octahedra and  a faceface with one Ba(4)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 11-22°. The Sb(1)-O(1) bond length is 2.01 Å. The Sb(1)-O(13) bond length is 1.96 Å. The Sb(1)-O(17) bond length is 2.01 Å. The Sb(1)-O(2) bond length is 1.98 Å. The Sb(1)-O(3) bond length is 1.94 Å. In the second Sb site, Sb(2) is bonded to one O(14), one O(15), one O(16), one O(4), one O(6), and one O(7) atom to form SbO6 octahedra that share corners with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and  a faceface with one Sb(3)O6 octahedra. The Sb(2)-O(14) bond length is 2.10 Å. The Sb(2)-O(15) bond length is 2.07 Å. The Sb(2)-O(16) bond length is 2.10 Å. The Sb(2)-O(4) bond length is 1.95 Å. The Sb(2)-O(6) bond length is 2.01 Å. The Sb(2)-O(7) bond length is 1.96 Å. In the third Sb site, Sb(3) is bonded to one O(10), one O(11), one O(14), one O(15), one O(16), and one O(5) atom to form SbO6 octahedra that share corners with three equivalent Co(1)O6 octahedra, faces with three equivalent Ba(4)O12 cuboctahedra, faces with three equivalent Ba(5)O12 cuboctahedra, and  a faceface with one Sb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-14°. The Sb(3)-O(10) bond length is 1.98 Å. The Sb(3)-O(11) bond length is 1.97 Å. The Sb(3)-O(14) bond length is 2.07 Å. The Sb(3)-O(15) bond length is 2.09 Å. The Sb(3)-O(16) bond length is 2.12 Å. The Sb(3)-O(5) bond length is 1.96 Å. In the fourth Sb site, Sb(4) is bonded in a 4-coordinate geometry to one O(12), one O(13), one O(18), and one O(8) atom. The Sb(4)-O(12) bond length is 2.01 Å. The Sb(4)-O(13) bond length is 2.48 Å. The Sb(4)-O(18) bond length is 1.99 Å. The Sb(4)-O(8) bond length is 2.03 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(2), one Co(1), and one Sb(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(2), one Co(1), and one Sb(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(2), one Co(1), and one Sb(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Ba(3), one Ba(5), two equivalent Ba(1), one Co(2), and one Sb(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Co(1), and one Sb(3) atom. In the sixth O site, O(6) is bonded in a 6-coordinate geometry to one Ba(3), one Ba(5), two equivalent Ba(1), one Co(2), and one Sb(2) atom. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to one Ba(5), two equivalent Ba(1), one Co(2), and one Sb(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(3), one Co(2), and one Sb(4) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(3), one Mg(1), and one Co(2) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Co(1), and one Sb(3) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one Ba(2), one Ba(5), two equivalent Ba(4), one Co(1), and one Sb(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 120 degrees geometry to one Ba(6), one Mg(1), and one Sb(4) atom. In the thirteenth O site, O(13) is bonded to one Ba(2), two equivalent Ba(6), one Sb(1), and one Sb(4) atom to form distorted corner-sharing OBa3Sb2 square pyramids. In the fourteenth O site, O(14) is bonded in a 2-coordinate geometry to one Ba(4), two equivalent Ba(5), one Sb(2), and one Sb(3) atom. In the fifteenth O site, O(15) is bonded in a distorted L-shaped geometry to one Ba(1), one Ba(4), two equivalent Ba(5), one Sb(2), and one Sb(3) atom. In the sixteenth O site, O(16) is bonded to one Ba(1), one Ba(4), two equivalent Ba(5), one Sb(2), and one Sb(3) atom to form distorted corner-sharing OBa4Sb2 octahedra. The corner-sharing octahedral tilt angles are 7°. In the seventeenth O site, O(17) is bonded in a 2-coordinate geometry to one Ba(2), two equivalent Ba(6), one Mg(1), and one Sb(1) atom. In the eighteenth O site, O(18) is bonded in a 2-coordinate geometry to two equivalent Ba(6), one Mg(1), and one Sb(4) atom.