Sr6Mg(W2O9)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 6-coordinate geometry to one O(10), one O(11), one O(16), one O(2), one O(4), one O(7), and one O(8) atom. In the second Sr site, Sr(2) is bonded to one O(10), one O(14), one O(17), one O(18), one O(2), and one O(5) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one W(3)O6 octahedra,  a cornercorner with one W(4)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one W(3)O6 octahedra, and  an edgeedge with one Sr(5)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 29-58°. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(13), one O(16), one O(4), one O(6), and one O(7) atom. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(13), one O(16), one O(3), one O(6), and one O(7) atom. In the fifth Sr site, Sr(5) is bonded to one O(13), one O(14), one O(15), one O(17), one O(8), and one O(9) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one W(3)O6 octahedra,  a cornercorner with one W(4)O6 octahedra,  an edgeedge with one W(4)O6 octahedra, and  an edgeedge with one Sr(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-40°. In the sixth Sr site, Sr(6) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(15), one O(17), one O(18), one O(3), one O(8), and one O(9) atom. Mg(1) is bonded to one O(1), one O(12), one O(4), one O(5), and one O(6) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one W(3)O6 octahedra,  a cornercorner with one W(4)O6 octahedra,  a cornercorner with one Sr(2)O6 pentagonal pyramid, and  an edgeedge with one W(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-33°. There are four inequivalent W sites. In the first W site, W(1) is bonded in a 6-coordinate geometry to one O(12), one O(14), one O(18), one O(2), one O(3), and one O(9) atom. In the second W site, W(2) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(16), one O(4), one O(5), and one O(6) atom. In the third W site, W(3) is bonded to one O(1), one O(10), one O(16), one O(17), one O(5), and one O(6) atom to form WO6 octahedra that share  a cornercorner with one Sr(2)O6 pentagonal pyramid,  a cornercorner with one Sr(5)O6 pentagonal pyramid,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Sr(2)O6 pentagonal pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. In the fourth W site, W(4) is bonded to one O(12), one O(14), one O(15), one O(3), one O(7), and one O(8) atom to form WO6 octahedra that share  a cornercorner with one Sr(2)O6 pentagonal pyramid,  a cornercorner with one Sr(5)O6 pentagonal pyramid,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Sr(5)O6 pentagonal pyramid. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Sr(6), one Mg(1), and one W(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one W(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(4), one Sr(6), one W(1), and one W(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(3), one Mg(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Sr(2), one Mg(1), one W(2), and one W(3) atom. In the sixth O site, O(6) is bonded to one Sr(3), one Sr(4), one Mg(1), one W(2), and one W(3) atom to form distorted OSr2MgW2 square pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  an edgeedge with one O(10)Sr4W square pyramid,  an edgeedge with one O(7)Sr3W trigonal pyramid, and  a faceface with one O(13)Sr3W trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(3), one Sr(4), and one W(4) atom to form distorted OSr3W trigonal pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  a cornercorner with one O(14)Sr2W2 trigonal pyramid,  an edgeedge with one O(6)Sr2MgW2 square pyramid,  an edgeedge with one O(10)Sr4W square pyramid,  an edgeedge with one O(13)Sr3W trigonal pyramid, and  an edgeedge with one O(8)Sr3W trigonal pyramid. In the eighth O site, O(8) is bonded to one Sr(1), one Sr(5), one Sr(6), and one W(4) atom to form distorted OSr3W trigonal pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  a cornercorner with one O(13)Sr3W trigonal pyramid, corners with two equivalent O(14)Sr2W2 trigonal pyramids, and  an edgeedge with one O(7)Sr3W trigonal pyramid. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Sr(5), one Sr(6), and one W(1) atom. In the tenth O site, O(10) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), and one W(3) atom to form distorted OSr4W square pyramids that share  a cornercorner with one O(6)Sr2MgW2 square pyramid,  a cornercorner with one O(14)Sr2W2 trigonal pyramid,  a cornercorner with one O(7)Sr3W trigonal pyramid,  a cornercorner with one O(8)Sr3W trigonal pyramid, corners with two equivalent O(13)Sr3W trigonal pyramids,  an edgeedge with one O(6)Sr2MgW2 square pyramid, and  an edgeedge with one O(7)Sr3W trigonal pyramid. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(4), and one W(2) atom. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Sr(6), one Mg(1), one W(1), and one W(4) atom. In the thirteenth O site, O(13) is bonded to one Sr(3), one Sr(4), one Sr(5), and one W(2) atom to form OSr3W trigonal pyramids that share corners with two equivalent O(10)Sr4W square pyramids,  a cornercorner with one O(14)Sr2W2 trigonal pyramid,  a cornercorner with one O(8)Sr3W trigonal pyramid,  an edgeedge with one O(7)Sr3W trigonal pyramid, and  a faceface with one O(6)Sr2MgW2 square pyramid. In the fourteenth O site, O(14) is bonded to one Sr(2), one Sr(5), one W(1), and one W(4) atom to form OSr2W2 trigonal pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  a cornercorner with one O(13)Sr3W trigonal pyramid,  a cornercorner with one O(7)Sr3W trigonal pyramid, and corners with two equivalent O(8)Sr3W trigonal pyramids. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Sr(5), one Sr(6), and one W(4) atom. In the sixteenth O site, O(16) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(3), one Sr(4), one W(2), and one W(3) atom. In the seventeenth O site, O(17) is bonded in a distorted see-saw-like geometry to one Sr(2), one Sr(5), one Sr(6), and one W(3) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(6), and one W(1) atom.
Sr6Mg(W2O9)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 6-coordinate geometry to one O(10), one O(11), one O(16), one O(2), one O(4), one O(7), and one O(8) atom. The Sr(1)-O(10) bond length is 2.62 Å. The Sr(1)-O(11) bond length is 2.70 Å. The Sr(1)-O(16) bond length is 3.21 Å. The Sr(1)-O(2) bond length is 2.82 Å. The Sr(1)-O(4) bond length is 2.37 Å. The Sr(1)-O(7) bond length is 2.65 Å. The Sr(1)-O(8) bond length is 2.71 Å. In the second Sr site, Sr(2) is bonded to one O(10), one O(14), one O(17), one O(18), one O(2), and one O(5) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one W(3)O6 octahedra,  a cornercorner with one W(4)O6 octahedra,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one W(3)O6 octahedra, and  an edgeedge with one Sr(5)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 29-58°. The Sr(2)-O(10) bond length is 2.57 Å. The Sr(2)-O(14) bond length is 2.56 Å. The Sr(2)-O(17) bond length is 2.66 Å. The Sr(2)-O(18) bond length is 2.42 Å. The Sr(2)-O(2) bond length is 2.52 Å. The Sr(2)-O(5) bond length is 2.51 Å. In the third Sr site, Sr(3) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(13), one O(16), one O(4), one O(6), and one O(7) atom. The Sr(3)-O(1) bond length is 2.62 Å. The Sr(3)-O(10) bond length is 2.87 Å. The Sr(3)-O(13) bond length is 2.67 Å. The Sr(3)-O(16) bond length is 2.48 Å. The Sr(3)-O(4) bond length is 2.50 Å. The Sr(3)-O(6) bond length is 2.58 Å. The Sr(3)-O(7) bond length is 2.42 Å. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(13), one O(16), one O(3), one O(6), and one O(7) atom. The Sr(4)-O(10) bond length is 2.63 Å. The Sr(4)-O(11) bond length is 2.57 Å. The Sr(4)-O(13) bond length is 2.58 Å. The Sr(4)-O(16) bond length is 2.73 Å. The Sr(4)-O(3) bond length is 2.53 Å. The Sr(4)-O(6) bond length is 2.81 Å. The Sr(4)-O(7) bond length is 2.68 Å. In the fifth Sr site, Sr(5) is bonded to one O(13), one O(14), one O(15), one O(17), one O(8), and one O(9) atom to form distorted SrO6 pentagonal pyramids that share  a cornercorner with one W(3)O6 octahedra,  a cornercorner with one W(4)O6 octahedra,  an edgeedge with one W(4)O6 octahedra, and  an edgeedge with one Sr(2)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 30-40°. The Sr(5)-O(13) bond length is 2.39 Å. The Sr(5)-O(14) bond length is 2.49 Å. The Sr(5)-O(15) bond length is 2.67 Å. The Sr(5)-O(17) bond length is 2.41 Å. The Sr(5)-O(8) bond length is 2.50 Å. The Sr(5)-O(9) bond length is 2.59 Å. In the sixth Sr site, Sr(6) is bonded in a 8-coordinate geometry to one O(1), one O(12), one O(15), one O(17), one O(18), one O(3), one O(8), and one O(9) atom. The Sr(6)-O(1) bond length is 2.66 Å. The Sr(6)-O(12) bond length is 2.52 Å. The Sr(6)-O(15) bond length is 2.55 Å. The Sr(6)-O(17) bond length is 2.64 Å. The Sr(6)-O(18) bond length is 2.89 Å. The Sr(6)-O(3) bond length is 3.02 Å. The Sr(6)-O(8) bond length is 2.71 Å. The Sr(6)-O(9) bond length is 2.64 Å. Mg(1) is bonded to one O(1), one O(12), one O(4), one O(5), and one O(6) atom to form distorted MgO5 trigonal bipyramids that share  a cornercorner with one W(3)O6 octahedra,  a cornercorner with one W(4)O6 octahedra,  a cornercorner with one Sr(2)O6 pentagonal pyramid, and  an edgeedge with one W(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 13-33°. The Mg(1)-O(1) bond length is 2.15 Å. The Mg(1)-O(12) bond length is 1.99 Å. The Mg(1)-O(4) bond length is 2.02 Å. The Mg(1)-O(5) bond length is 2.24 Å. The Mg(1)-O(6) bond length is 2.28 Å. There are four inequivalent W sites. In the first W site, W(1) is bonded in a 6-coordinate geometry to one O(12), one O(14), one O(18), one O(2), one O(3), and one O(9) atom. The W(1)-O(12) bond length is 2.28 Å. The W(1)-O(14) bond length is 2.14 Å. The W(1)-O(18) bond length is 1.82 Å. The W(1)-O(2) bond length is 1.86 Å. The W(1)-O(3) bond length is 2.06 Å. The W(1)-O(9) bond length is 1.84 Å. In the second W site, W(2) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(16), one O(4), one O(5), and one O(6) atom. The W(2)-O(11) bond length is 1.83 Å. The W(2)-O(13) bond length is 1.97 Å. The W(2)-O(16) bond length is 2.06 Å. The W(2)-O(4) bond length is 1.99 Å. The W(2)-O(5) bond length is 2.11 Å. The W(2)-O(6) bond length is 2.36 Å. In the third W site, W(3) is bonded to one O(1), one O(10), one O(16), one O(17), one O(5), and one O(6) atom to form WO6 octahedra that share  a cornercorner with one Sr(2)O6 pentagonal pyramid,  a cornercorner with one Sr(5)O6 pentagonal pyramid,  a cornercorner with one Mg(1)O5 trigonal bipyramid,  an edgeedge with one Sr(2)O6 pentagonal pyramid, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The W(3)-O(1) bond length is 1.94 Å. The W(3)-O(10) bond length is 2.01 Å. The W(3)-O(16) bond length is 2.14 Å. The W(3)-O(17) bond length is 1.94 Å. The W(3)-O(5) bond length is 2.16 Å. The W(3)-O(6) bond length is 2.06 Å. In the fourth W site, W(4) is bonded to one O(12), one O(14), one O(15), one O(3), one O(7), and one O(8) atom to form WO6 octahedra that share  a cornercorner with one Sr(2)O6 pentagonal pyramid,  a cornercorner with one Sr(5)O6 pentagonal pyramid,  a cornercorner with one Mg(1)O5 trigonal bipyramid, and  an edgeedge with one Sr(5)O6 pentagonal pyramid. The W(4)-O(12) bond length is 2.10 Å. The W(4)-O(14) bond length is 2.05 Å. The W(4)-O(15) bond length is 1.84 Å. The W(4)-O(3) bond length is 2.10 Å. The W(4)-O(7) bond length is 1.88 Å. The W(4)-O(8) bond length is 1.87 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Sr(6), one Mg(1), and one W(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(2), and one W(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Sr(4), one Sr(6), one W(1), and one W(4) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(3), one Mg(1), and one W(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Sr(2), one Mg(1), one W(2), and one W(3) atom. In the sixth O site, O(6) is bonded to one Sr(3), one Sr(4), one Mg(1), one W(2), and one W(3) atom to form distorted OSr2MgW2 square pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  an edgeedge with one O(10)Sr4W square pyramid,  an edgeedge with one O(7)Sr3W trigonal pyramid, and  a faceface with one O(13)Sr3W trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(3), one Sr(4), and one W(4) atom to form distorted OSr3W trigonal pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  a cornercorner with one O(14)Sr2W2 trigonal pyramid,  an edgeedge with one O(6)Sr2MgW2 square pyramid,  an edgeedge with one O(10)Sr4W square pyramid,  an edgeedge with one O(13)Sr3W trigonal pyramid, and  an edgeedge with one O(8)Sr3W trigonal pyramid. In the eighth O site, O(8) is bonded to one Sr(1), one Sr(5), one Sr(6), and one W(4) atom to form distorted OSr3W trigonal pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  a cornercorner with one O(13)Sr3W trigonal pyramid, corners with two equivalent O(14)Sr2W2 trigonal pyramids, and  an edgeedge with one O(7)Sr3W trigonal pyramid. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one Sr(5), one Sr(6), and one W(1) atom. In the tenth O site, O(10) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(4), and one W(3) atom to form distorted OSr4W square pyramids that share  a cornercorner with one O(6)Sr2MgW2 square pyramid,  a cornercorner with one O(14)Sr2W2 trigonal pyramid,  a cornercorner with one O(7)Sr3W trigonal pyramid,  a cornercorner with one O(8)Sr3W trigonal pyramid, corners with two equivalent O(13)Sr3W trigonal pyramids,  an edgeedge with one O(6)Sr2MgW2 square pyramid, and  an edgeedge with one O(7)Sr3W trigonal pyramid. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Sr(1), one Sr(4), and one W(2) atom. In the twelfth O site, O(12) is bonded in a distorted rectangular see-saw-like geometry to one Sr(6), one Mg(1), one W(1), and one W(4) atom. In the thirteenth O site, O(13) is bonded to one Sr(3), one Sr(4), one Sr(5), and one W(2) atom to form OSr3W trigonal pyramids that share corners with two equivalent O(10)Sr4W square pyramids,  a cornercorner with one O(14)Sr2W2 trigonal pyramid,  a cornercorner with one O(8)Sr3W trigonal pyramid,  an edgeedge with one O(7)Sr3W trigonal pyramid, and  a faceface with one O(6)Sr2MgW2 square pyramid. In the fourteenth O site, O(14) is bonded to one Sr(2), one Sr(5), one W(1), and one W(4) atom to form OSr2W2 trigonal pyramids that share  a cornercorner with one O(10)Sr4W square pyramid,  a cornercorner with one O(13)Sr3W trigonal pyramid,  a cornercorner with one O(7)Sr3W trigonal pyramid, and corners with two equivalent O(8)Sr3W trigonal pyramids. In the fifteenth O site, O(15) is bonded in a distorted T-shaped geometry to one Sr(5), one Sr(6), and one W(4) atom. In the sixteenth O site, O(16) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(3), one Sr(4), one W(2), and one W(3) atom. In the seventeenth O site, O(17) is bonded in a distorted see-saw-like geometry to one Sr(2), one Sr(5), one Sr(6), and one W(3) atom. In the eighteenth O site, O(18) is bonded in a 3-coordinate geometry to one Sr(2), one Sr(6), and one W(1) atom.