Ba6MgNb2Ir(O6Cl)2 crystallizes in the triclinic P1 space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(11), one O(3), one O(7), one Cl(2), and two equivalent Cl(1) atoms to form a mixture of distorted edge and corner-sharing BaCl3O3 pentagonal pyramids. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to one O(12), one O(2), one O(4), two equivalent O(5), and one Cl(2) atom. In the third Ba site, Ba(3) is bonded to one O(2), one O(4), one O(5), one Cl(1), and two equivalent Cl(2) atoms to form distorted BaCl3O3 pentagonal pyramids that share corners with three equivalent Nb(1)O6 octahedra, corners with two equivalent Ba(3)Cl3O3 pentagonal pyramids, and edges with two equivalent Ba(1)Cl3O3 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 22-31°. In the fourth Ba site, Ba(4) is bonded in a 10-coordinate geometry to one Mg(1), one O(1), one O(10), one O(2), one O(4), one O(5), one O(6), one O(8), and two equivalent O(12) atoms. In the fifth Ba site, Ba(5) is bonded in a 11-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(7), two equivalent O(6), two equivalent O(8), and two equivalent O(9) atoms. In the sixth Ba site, Ba(6) is bonded in a 8-coordinate geometry to one O(11), one O(3), one O(6), one O(8), one O(9), two equivalent O(7), and one Cl(1) atom. Mg(1) is bonded to one Ba(4), one O(1), one O(10), one O(6), one O(8), and one O(9) atom to form distorted MgBaO5 square pyramids that share  a cornercorner with one O(5)Ba4Nb trigonal bipyramid and  an edgeedge with one Nb(1)O6 octahedra. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(10), one O(12), one O(2), one O(4), and one O(5) atom to form NbO6 octahedra that share corners with three equivalent Ba(3)Cl3O3 pentagonal pyramids and  an edgeedge with one Mg(1)BaO5 square pyramid. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(11), one O(3), one O(6), one O(7), one O(8), and one O(9) atom. Ir(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(12), one O(6), one O(8), and one O(9) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ba(4), one Ba(5), one Mg(1), one Nb(1), and one Ir(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ba(2), one Ba(3), one Ba(4), and one Nb(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Ba(1), one Ba(5), one Ba(6), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Ba(2), one Ba(3), one Ba(4), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one Ba(3), one Ba(4), two equivalent Ba(2), and one Nb(1) atom to form distorted OBa4Nb trigonal bipyramids that share  a cornercorner with one Mg(1)BaO5 square pyramid and corners with two equivalent O(5)Ba4Nb trigonal bipyramids. In the sixth O site, O(6) is bonded in a 7-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(5), one Mg(1), one Nb(2), and one Ir(1) atom. In the seventh O site, O(7) is bonded to one Ba(1), one Ba(5), two equivalent Ba(6), and one Nb(2) atom to form distorted corner-sharing OBa4Nb square pyramids. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(5), one Mg(1), one Nb(2), and one Ir(1) atom. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one Ba(6), two equivalent Ba(5), one Mg(1), one Nb(2), and one Ir(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Ba(4), one Ba(5), one Mg(1), one Nb(1), and one Ir(1) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(5), one Ba(6), and one Nb(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Ba(2), two equivalent Ba(4), one Nb(1), and one Ir(1) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a distorted see-saw-like geometry to one Ba(3), one Ba(6), and two equivalent Ba(1) atoms. In the second Cl site, Cl(2) is bonded in a distorted see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Ba(3) atoms.
Ba6MgNb2Ir(O6Cl)2 crystallizes in the triclinic P1 space group. There are six inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to one O(11), one O(3), one O(7), one Cl(2), and two equivalent Cl(1) atoms to form a mixture of distorted edge and corner-sharing BaCl3O3 pentagonal pyramids. The Ba(1)-O(11) bond length is 2.58 Å. The Ba(1)-O(3) bond length is 2.58 Å. The Ba(1)-O(7) bond length is 2.58 Å. The Ba(1)-Cl(2) bond length is 3.28 Å. There is one shorter (3.38 Å) and one longer (3.39 Å) Ba(1)-Cl(1) bond length. In the second Ba site, Ba(2) is bonded in a 6-coordinate geometry to one O(12), one O(2), one O(4), two equivalent O(5), and one Cl(2) atom. The Ba(2)-O(12) bond length is 2.44 Å. The Ba(2)-O(2) bond length is 2.68 Å. The Ba(2)-O(4) bond length is 2.67 Å. Both Ba(2)-O(5) bond lengths are 2.98 Å. The Ba(2)-Cl(2) bond length is 3.10 Å. In the third Ba site, Ba(3) is bonded to one O(2), one O(4), one O(5), one Cl(1), and two equivalent Cl(2) atoms to form distorted BaCl3O3 pentagonal pyramids that share corners with three equivalent Nb(1)O6 octahedra, corners with two equivalent Ba(3)Cl3O3 pentagonal pyramids, and edges with two equivalent Ba(1)Cl3O3 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 22-31°. The Ba(3)-O(2) bond length is 2.59 Å. The Ba(3)-O(4) bond length is 2.59 Å. The Ba(3)-O(5) bond length is 2.74 Å. The Ba(3)-Cl(1) bond length is 3.15 Å. There is one shorter (3.31 Å) and one longer (3.32 Å) Ba(3)-Cl(2) bond length. In the fourth Ba site, Ba(4) is bonded in a 10-coordinate geometry to one Mg(1), one O(1), one O(10), one O(2), one O(4), one O(5), one O(6), one O(8), and two equivalent O(12) atoms. The Ba(4)-Mg(1) bond length is 2.97 Å. The Ba(4)-O(1) bond length is 2.69 Å. The Ba(4)-O(10) bond length is 2.69 Å. The Ba(4)-O(2) bond length is 2.80 Å. The Ba(4)-O(4) bond length is 2.80 Å. The Ba(4)-O(5) bond length is 2.69 Å. The Ba(4)-O(6) bond length is 3.11 Å. The Ba(4)-O(8) bond length is 3.16 Å. There is one shorter (2.99 Å) and one longer (3.02 Å) Ba(4)-O(12) bond length. In the fifth Ba site, Ba(5) is bonded in a 11-coordinate geometry to one O(1), one O(10), one O(11), one O(3), one O(7), two equivalent O(6), two equivalent O(8), and two equivalent O(9) atoms. The Ba(5)-O(1) bond length is 2.88 Å. The Ba(5)-O(10) bond length is 2.88 Å. The Ba(5)-O(11) bond length is 3.05 Å. The Ba(5)-O(3) bond length is 3.05 Å. The Ba(5)-O(7) bond length is 2.68 Å. There is one shorter (2.94 Å) and one longer (3.39 Å) Ba(5)-O(6) bond length. There is one shorter (2.91 Å) and one longer (3.41 Å) Ba(5)-O(8) bond length. There is one shorter (3.00 Å) and one longer (3.01 Å) Ba(5)-O(9) bond length. In the sixth Ba site, Ba(6) is bonded in a 8-coordinate geometry to one O(11), one O(3), one O(6), one O(8), one O(9), two equivalent O(7), and one Cl(1) atom. The Ba(6)-O(11) bond length is 2.65 Å. The Ba(6)-O(3) bond length is 2.66 Å. The Ba(6)-O(6) bond length is 3.07 Å. The Ba(6)-O(8) bond length is 3.07 Å. The Ba(6)-O(9) bond length is 2.52 Å. There is one shorter (2.97 Å) and one longer (2.99 Å) Ba(6)-O(7) bond length. The Ba(6)-Cl(1) bond length is 3.14 Å. Mg(1) is bonded to one Ba(4), one O(1), one O(10), one O(6), one O(8), and one O(9) atom to form distorted MgBaO5 square pyramids that share  a cornercorner with one O(5)Ba4Nb trigonal bipyramid and  an edgeedge with one Nb(1)O6 octahedra. The Mg(1)-O(1) bond length is 2.18 Å. The Mg(1)-O(10) bond length is 2.18 Å. The Mg(1)-O(6) bond length is 2.18 Å. The Mg(1)-O(8) bond length is 2.22 Å. The Mg(1)-O(9) bond length is 1.92 Å. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(10), one O(12), one O(2), one O(4), and one O(5) atom to form NbO6 octahedra that share corners with three equivalent Ba(3)Cl3O3 pentagonal pyramids and  an edgeedge with one Mg(1)BaO5 square pyramid. The Nb(1)-O(1) bond length is 2.24 Å. The Nb(1)-O(10) bond length is 2.24 Å. The Nb(1)-O(12) bond length is 2.05 Å. The Nb(1)-O(2) bond length is 1.93 Å. The Nb(1)-O(4) bond length is 1.93 Å. The Nb(1)-O(5) bond length is 2.01 Å. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(11), one O(3), one O(6), one O(7), one O(8), and one O(9) atom. The Nb(2)-O(11) bond length is 1.91 Å. The Nb(2)-O(3) bond length is 1.91 Å. The Nb(2)-O(6) bond length is 2.42 Å. The Nb(2)-O(7) bond length is 2.03 Å. The Nb(2)-O(8) bond length is 2.38 Å. The Nb(2)-O(9) bond length is 2.16 Å. Ir(1) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(12), one O(6), one O(8), and one O(9) atom. The Ir(1)-O(1) bond length is 2.18 Å. The Ir(1)-O(10) bond length is 2.18 Å. The Ir(1)-O(12) bond length is 2.13 Å. The Ir(1)-O(6) bond length is 2.14 Å. The Ir(1)-O(8) bond length is 2.14 Å. The Ir(1)-O(9) bond length is 2.43 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one Ba(4), one Ba(5), one Mg(1), one Nb(1), and one Ir(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Ba(2), one Ba(3), one Ba(4), and one Nb(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Ba(1), one Ba(5), one Ba(6), and one Nb(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Ba(2), one Ba(3), one Ba(4), and one Nb(1) atom. In the fifth O site, O(5) is bonded to one Ba(3), one Ba(4), two equivalent Ba(2), and one Nb(1) atom to form distorted OBa4Nb trigonal bipyramids that share  a cornercorner with one Mg(1)BaO5 square pyramid and corners with two equivalent O(5)Ba4Nb trigonal bipyramids. In the sixth O site, O(6) is bonded in a 7-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(5), one Mg(1), one Nb(2), and one Ir(1) atom. In the seventh O site, O(7) is bonded to one Ba(1), one Ba(5), two equivalent Ba(6), and one Nb(2) atom to form distorted corner-sharing OBa4Nb square pyramids. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Ba(4), one Ba(6), two equivalent Ba(5), one Mg(1), one Nb(2), and one Ir(1) atom. In the ninth O site, O(9) is bonded in a 6-coordinate geometry to one Ba(6), two equivalent Ba(5), one Mg(1), one Nb(2), and one Ir(1) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to one Ba(4), one Ba(5), one Mg(1), one Nb(1), and one Ir(1) atom. In the eleventh O site, O(11) is bonded in a 4-coordinate geometry to one Ba(1), one Ba(5), one Ba(6), and one Nb(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Ba(2), two equivalent Ba(4), one Nb(1), and one Ir(1) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a distorted see-saw-like geometry to one Ba(3), one Ba(6), and two equivalent Ba(1) atoms. In the second Cl site, Cl(2) is bonded in a distorted see-saw-like geometry to one Ba(1), one Ba(2), and two equivalent Ba(3) atoms.