Sr6Mg(Te4O11)2 crystallizes in the triclinic P1 space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(10), one O(13), one O(15), one O(17), one O(18), one O(19), one O(6), and one O(8) atom. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to one O(14), one O(17), one O(18), one O(20), one O(5), and one O(7) atom. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(12), one O(15), one O(17), one O(19), and one O(5) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(16), one O(18), one O(20), one O(6), and one O(9) atom. In the fifth Sr site, Sr(5) is bonded in a 9-coordinate geometry to one O(1), one O(11), one O(14), one O(19), one O(2), one O(22), one O(3), one O(4), and one O(9) atom. In the sixth Sr site, Sr(6) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(12), one O(13), one O(2), one O(20), one O(21), one O(3), and one O(4) atom. Mg(1) is bonded in a distorted trigonal bipyramidal geometry to one O(14), one O(15), one O(16), one O(6), and one O(9) atom. There are eight inequivalent Te sites. In the first Te site, Te(1) is bonded in a 3-coordinate geometry to one O(19), one O(2), and one O(5) atom. In the second Te site, Te(2) is bonded in a 3-coordinate geometry to one O(1), one O(20), one O(4), and one O(6) atom. In the third Te site, Te(3) is bonded in a rectangular see-saw-like geometry to one O(11), one O(18), one O(22), and one O(7) atom. In the fourth Te site, Te(4) is bonded in a distorted rectangular see-saw-like geometry to one O(12), one O(17), one O(21), and one O(8) atom. In the fifth Te site, Te(5) is bonded in a distorted T-shaped geometry to one O(14), one O(15), and one O(21) atom. In the sixth Te site, Te(6) is bonded in a 4-coordinate geometry to one O(13), one O(16), one O(21), and one O(22) atom. In the seventh Te site, Te(7) is bonded in a trigonal non-coplanar geometry to one O(3), one O(8), and one O(9) atom. In the eighth Te site, Te(8) is bonded in a trigonal non-coplanar geometry to one O(10), one O(4), and one O(7) atom. There are twenty-two inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Sr(5), one Sr(6), and one Te(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(5), one Sr(6), and one Te(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(5), one Sr(6), and one Te(7) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sr(5), one Sr(6), one Te(2), and one Te(8) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one Te(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(4), one Mg(1), and one Te(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Sr(2), one Te(3), and one Te(8) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1), one Te(4), and one Te(7) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Sr(4), one Sr(5), one Mg(1), and one Te(7) atom. In the tenth O site, O(10) is bonded to one Sr(1), one Sr(3), one Sr(6), and one Te(8) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(21)SrTe3 tetrahedra and corners with two equivalent O(17)Sr3Te tetrahedra. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(3), one Sr(4), one Sr(5), and one Te(3) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to one Sr(3), one Sr(4), one Sr(6), and one Te(4) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Sr(1), one Sr(6), and one Te(6) atom. In the fourteenth O site, O(14) is bonded to one Sr(2), one Sr(5), one Mg(1), and one Te(5) atom to form distorted OSr2MgTe trigonal pyramids that share  a cornercorner with one O(17)Sr3Te tetrahedra and  a cornercorner with one O(21)SrTe3 tetrahedra. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Mg(1), and one Te(5) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Sr(4), one Mg(1), and one Te(6) atom. In the seventeenth O site, O(17) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Te(4) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(21)SrTe3 tetrahedra, corners with two equivalent O(10)Sr3Te tetrahedra, and  a cornercorner with one O(14)Sr2MgTe trigonal pyramid. In the eighteenth O site, O(18) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(4), and one Te(3) atom. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Sr(5), and one Te(1) atom. In the twentieth O site, O(20) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sr(6), and one Te(2) atom. In the twenty-first O site, O(21) is bonded to one Sr(6), one Te(4), one Te(5), and one Te(6) atom to form distorted OSrTe3 tetrahedra that share  a cornercorner with one O(10)Sr3Te tetrahedra,  a cornercorner with one O(17)Sr3Te tetrahedra, and  a cornercorner with one O(14)Sr2MgTe trigonal pyramid. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Sr(5), one Te(3), and one Te(6) atom.
Sr6Mg(Te4O11)2 crystallizes in the triclinic P1 space group. There are six inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(10), one O(13), one O(15), one O(17), one O(18), one O(19), one O(6), and one O(8) atom. The Sr(1)-O(10) bond length is 2.81 Å. The Sr(1)-O(13) bond length is 2.53 Å. The Sr(1)-O(15) bond length is 2.42 Å. The Sr(1)-O(17) bond length is 2.69 Å. The Sr(1)-O(18) bond length is 3.03 Å. The Sr(1)-O(19) bond length is 2.64 Å. The Sr(1)-O(6) bond length is 2.79 Å. The Sr(1)-O(8) bond length is 2.70 Å. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to one O(14), one O(17), one O(18), one O(20), one O(5), and one O(7) atom. The Sr(2)-O(14) bond length is 2.74 Å. The Sr(2)-O(17) bond length is 2.58 Å. The Sr(2)-O(18) bond length is 2.45 Å. The Sr(2)-O(20) bond length is 2.71 Å. The Sr(2)-O(5) bond length is 2.50 Å. The Sr(2)-O(7) bond length is 2.77 Å. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(12), one O(15), one O(17), one O(19), and one O(5) atom. The Sr(3)-O(10) bond length is 2.59 Å. The Sr(3)-O(11) bond length is 2.56 Å. The Sr(3)-O(12) bond length is 2.87 Å. The Sr(3)-O(15) bond length is 2.58 Å. The Sr(3)-O(17) bond length is 2.79 Å. The Sr(3)-O(19) bond length is 2.92 Å. The Sr(3)-O(5) bond length is 2.58 Å. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(11), one O(12), one O(16), one O(18), one O(20), one O(6), and one O(9) atom. The Sr(4)-O(11) bond length is 2.53 Å. The Sr(4)-O(12) bond length is 2.36 Å. The Sr(4)-O(16) bond length is 2.61 Å. The Sr(4)-O(18) bond length is 2.63 Å. The Sr(4)-O(20) bond length is 2.77 Å. The Sr(4)-O(6) bond length is 2.61 Å. The Sr(4)-O(9) bond length is 2.80 Å. In the fifth Sr site, Sr(5) is bonded in a 9-coordinate geometry to one O(1), one O(11), one O(14), one O(19), one O(2), one O(22), one O(3), one O(4), and one O(9) atom. The Sr(5)-O(1) bond length is 2.65 Å. The Sr(5)-O(11) bond length is 3.28 Å. The Sr(5)-O(14) bond length is 2.75 Å. The Sr(5)-O(19) bond length is 3.05 Å. The Sr(5)-O(2) bond length is 2.79 Å. The Sr(5)-O(22) bond length is 2.78 Å. The Sr(5)-O(3) bond length is 2.70 Å. The Sr(5)-O(4) bond length is 2.65 Å. The Sr(5)-O(9) bond length is 2.64 Å. In the sixth Sr site, Sr(6) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(12), one O(13), one O(2), one O(20), one O(21), one O(3), and one O(4) atom. The Sr(6)-O(1) bond length is 2.78 Å. The Sr(6)-O(10) bond length is 2.70 Å. The Sr(6)-O(12) bond length is 3.21 Å. The Sr(6)-O(13) bond length is 2.60 Å. The Sr(6)-O(2) bond length is 2.59 Å. The Sr(6)-O(20) bond length is 3.05 Å. The Sr(6)-O(21) bond length is 2.81 Å. The Sr(6)-O(3) bond length is 2.76 Å. The Sr(6)-O(4) bond length is 2.85 Å. Mg(1) is bonded in a distorted trigonal bipyramidal geometry to one O(14), one O(15), one O(16), one O(6), and one O(9) atom. The Mg(1)-O(14) bond length is 2.00 Å. The Mg(1)-O(15) bond length is 2.02 Å. The Mg(1)-O(16) bond length is 2.00 Å. The Mg(1)-O(6) bond length is 1.95 Å. The Mg(1)-O(9) bond length is 2.17 Å. There are eight inequivalent Te sites. In the first Te site, Te(1) is bonded in a 3-coordinate geometry to one O(19), one O(2), and one O(5) atom. The Te(1)-O(19) bond length is 1.90 Å. The Te(1)-O(2) bond length is 1.88 Å. The Te(1)-O(5) bond length is 1.93 Å. In the second Te site, Te(2) is bonded in a 3-coordinate geometry to one O(1), one O(20), one O(4), and one O(6) atom. The Te(2)-O(1) bond length is 1.88 Å. The Te(2)-O(20) bond length is 1.91 Å. The Te(2)-O(4) bond length is 2.69 Å. The Te(2)-O(6) bond length is 1.92 Å. In the third Te site, Te(3) is bonded in a rectangular see-saw-like geometry to one O(11), one O(18), one O(22), and one O(7) atom. The Te(3)-O(11) bond length is 1.89 Å. The Te(3)-O(18) bond length is 1.89 Å. The Te(3)-O(22) bond length is 2.09 Å. The Te(3)-O(7) bond length is 2.24 Å. In the fourth Te site, Te(4) is bonded in a distorted rectangular see-saw-like geometry to one O(12), one O(17), one O(21), and one O(8) atom. The Te(4)-O(12) bond length is 1.88 Å. The Te(4)-O(17) bond length is 1.93 Å. The Te(4)-O(21) bond length is 1.97 Å. The Te(4)-O(8) bond length is 2.56 Å. In the fifth Te site, Te(5) is bonded in a distorted T-shaped geometry to one O(14), one O(15), and one O(21) atom. The Te(5)-O(14) bond length is 2.01 Å. The Te(5)-O(15) bond length is 2.04 Å. The Te(5)-O(21) bond length is 2.41 Å. In the sixth Te site, Te(6) is bonded in a 4-coordinate geometry to one O(13), one O(16), one O(21), and one O(22) atom. The Te(6)-O(13) bond length is 1.87 Å. The Te(6)-O(16) bond length is 1.94 Å. The Te(6)-O(21) bond length is 2.57 Å. The Te(6)-O(22) bond length is 1.99 Å. In the seventh Te site, Te(7) is bonded in a trigonal non-coplanar geometry to one O(3), one O(8), and one O(9) atom. The Te(7)-O(3) bond length is 1.89 Å. The Te(7)-O(8) bond length is 1.90 Å. The Te(7)-O(9) bond length is 1.95 Å. In the eighth Te site, Te(8) is bonded in a trigonal non-coplanar geometry to one O(10), one O(4), and one O(7) atom. The Te(8)-O(10) bond length is 1.88 Å. The Te(8)-O(4) bond length is 1.89 Å. The Te(8)-O(7) bond length is 1.93 Å. There are twenty-two inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Sr(5), one Sr(6), and one Te(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(5), one Sr(6), and one Te(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(5), one Sr(6), and one Te(7) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sr(5), one Sr(6), one Te(2), and one Te(8) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(3), and one Te(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(4), one Mg(1), and one Te(2) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Sr(2), one Te(3), and one Te(8) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1), one Te(4), and one Te(7) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to one Sr(4), one Sr(5), one Mg(1), and one Te(7) atom. In the tenth O site, O(10) is bonded to one Sr(1), one Sr(3), one Sr(6), and one Te(8) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(21)SrTe3 tetrahedra and corners with two equivalent O(17)Sr3Te tetrahedra. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(3), one Sr(4), one Sr(5), and one Te(3) atom. In the twelfth O site, O(12) is bonded in a 2-coordinate geometry to one Sr(3), one Sr(4), one Sr(6), and one Te(4) atom. In the thirteenth O site, O(13) is bonded in a trigonal planar geometry to one Sr(1), one Sr(6), and one Te(6) atom. In the fourteenth O site, O(14) is bonded to one Sr(2), one Sr(5), one Mg(1), and one Te(5) atom to form distorted OSr2MgTe trigonal pyramids that share  a cornercorner with one O(17)Sr3Te tetrahedra and  a cornercorner with one O(21)SrTe3 tetrahedra. In the fifteenth O site, O(15) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Mg(1), and one Te(5) atom. In the sixteenth O site, O(16) is bonded in a 3-coordinate geometry to one Sr(4), one Mg(1), and one Te(6) atom. In the seventeenth O site, O(17) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Te(4) atom to form distorted OSr3Te tetrahedra that share  a cornercorner with one O(21)SrTe3 tetrahedra, corners with two equivalent O(10)Sr3Te tetrahedra, and  a cornercorner with one O(14)Sr2MgTe trigonal pyramid. In the eighteenth O site, O(18) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(4), and one Te(3) atom. In the nineteenth O site, O(19) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Sr(5), and one Te(1) atom. In the twentieth O site, O(20) is bonded in a 4-coordinate geometry to one Sr(2), one Sr(4), one Sr(6), and one Te(2) atom. In the twenty-first O site, O(21) is bonded to one Sr(6), one Te(4), one Te(5), and one Te(6) atom to form distorted OSrTe3 tetrahedra that share  a cornercorner with one O(10)Sr3Te tetrahedra,  a cornercorner with one O(17)Sr3Te tetrahedra, and  a cornercorner with one O(14)Sr2MgTe trigonal pyramid. In the twenty-second O site, O(22) is bonded in a 3-coordinate geometry to one Sr(5), one Te(3), and one Te(6) atom.