Sr6Nb2O11 crystallizes in the triclinic P1 space group. There are twelve inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(14), one O(19), one O(3), one O(4), and one O(5) atom. In the second Sr site, Sr(2) is bonded to one O(1), one O(14), one O(2), one O(3), one O(4), and one O(5) atom to form distorted SrO6 octahedra that share  a cornercorner with one Sr(10)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and corners with three equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 12-36°. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(6), one O(7), one O(8), and one O(9) atom. In the fourth Sr site, Sr(4) is bonded to one O(10), one O(6), one O(7), one O(8), and one O(9) atom to form distorted SrO5 trigonal bipyramids that share corners with three equivalent Nb(2)O6 octahedra and corners with two equivalent Nb(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 10-40°. In the fifth Sr site, Sr(5) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(9) atom. In the sixth Sr site, Sr(6) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(13), one O(15), and one O(16) atom. In the seventh Sr site, Sr(7) is bonded to one O(11), one O(12), one O(13), one O(15), one O(16), and one O(17) atom to form distorted SrO6 pentagonal pyramids that share corners with three equivalent Nb(4)O6 octahedra and corners with three equivalent Nb(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-34°. In the eighth Sr site, Sr(8) is bonded in a 6-coordinate geometry to one O(12), one O(17), one O(18), one O(20), one O(21), and one O(22) atom. In the ninth Sr site, Sr(9) is bonded in a 6-coordinate geometry to one O(10), one O(13), one O(15), one O(7), one O(8), and one O(9) atom. In the tenth Sr site, Sr(10) is bonded to one O(14), one O(18), one O(19), one O(20), one O(21), and one O(22) atom to form SrO6 octahedra that share  a cornercorner with one Sr(2)O6 octahedra, corners with three equivalent Nb(4)O6 octahedra, and corners with three equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 21-32°. In the eleventh Sr site, Sr(11) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(16), one O(17), one O(18), and one O(21) atom. In the twelfth Sr site, Sr(12) is bonded in a 7-coordinate geometry to one O(14), one O(18), one O(19), one O(20), one O(21), one O(22), and one O(3) atom. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(14), one O(19), one O(22), one O(3), and one O(4) atom to form NbO5 trigonal bipyramids that share corners with three equivalent Sr(10)O6 octahedra and corners with three equivalent Sr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-74°. In the second Nb site, Nb(2) is bonded to one O(1), one O(2), one O(5), one O(6), one O(8), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Sr(2)O6 octahedra and corners with three equivalent Sr(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 12-36°. In the third Nb site, Nb(3) is bonded to one O(10), one O(11), one O(13), one O(15), and one O(7) atom to form NbO5 trigonal bipyramids that share corners with three equivalent Sr(7)O6 pentagonal pyramids and corners with two equivalent Sr(4)O5 trigonal bipyramids. In the fourth Nb site, Nb(4) is bonded to one O(12), one O(16), one O(17), one O(18), one O(20), and one O(21) atom to form NbO6 octahedra that share corners with three equivalent Sr(10)O6 octahedra and corners with three equivalent Sr(7)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 21-24°. There are twenty-two inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(5), and one Nb(2) atom to form distorted OSr4Nb square pyramids that share  a cornercorner with one O(9)Sr4Nb square pyramid,  an edgeedge with one O(9)Sr4Nb square pyramid, and edges with two equivalent O(2)Sr3Nb tetrahedra. In the second O site, O(2) is bonded to one Sr(2), one Sr(3), one Sr(5), and one Nb(2) atom to form a mixture of distorted corner and edge-sharing OSr3Nb tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(12), one Sr(2), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(5), and one Nb(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(5), and one Nb(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sr(3), one Sr(4), one Sr(5), and one Nb(2) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Sr(4), one Sr(9), and one Nb(3) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Sr(3), one Sr(4), one Sr(9), and one Nb(2) atom. In the ninth O site, O(9) is bonded to one Sr(3), one Sr(4), one Sr(5), one Sr(9), and one Nb(2) atom to form distorted OSr4Nb square pyramids that share  a cornercorner with one O(1)Sr4Nb square pyramid, corners with three equivalent O(2)Sr3Nb tetrahedra,  an edgeedge with one O(1)Sr4Nb square pyramid, and  an edgeedge with one O(10)Sr3Nb tetrahedra. In the tenth O site, O(10) is bonded to one Sr(4), one Sr(6), one Sr(9), and one Nb(3) atom to form distorted OSr3Nb tetrahedra that share  a cornercorner with one O(12)Sr4Nb square pyramid,  an edgeedge with one O(9)Sr4Nb square pyramid, and  an edgeedge with one O(11)Sr3Nb trigonal pyramid. In the eleventh O site, O(11) is bonded to one Sr(11), one Sr(6), one Sr(7), and one Nb(3) atom to form distorted OSr3Nb trigonal pyramids that share  a cornercorner with one O(12)Sr4Nb square pyramid,  an edgeedge with one O(12)Sr4Nb square pyramid, and  an edgeedge with one O(10)Sr3Nb tetrahedra. In the twelfth O site, O(12) is bonded to one Sr(11), one Sr(6), one Sr(7), one Sr(8), and one Nb(4) atom to form a mixture of distorted corner and edge-sharing OSr4Nb square pyramids. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Sr(6), one Sr(7), one Sr(9), and one Nb(3) atom. In the fourteenth O site, O(14) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(10), one Sr(12), one Sr(2), and one Nb(1) atom. In the fifteenth O site, O(15) is bonded in a 1-coordinate geometry to one Sr(6), one Sr(7), one Sr(9), and one Nb(3) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Sr(11), one Sr(6), one Sr(7), and one Nb(4) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Sr(11), one Sr(7), one Sr(8), and one Nb(4) atom. In the eighteenth O site, O(18) is bonded in a 5-coordinate geometry to one Sr(10), one Sr(11), one Sr(12), one Sr(8), and one Nb(4) atom. In the nineteenth O site, O(19) is bonded in a distorted see-saw-like geometry to one Sr(1), one Sr(10), one Sr(12), and one Nb(1) atom. In the twentieth O site, O(20) is bonded in a 3-coordinate geometry to one Sr(10), one Sr(12), one Sr(8), and one Nb(4) atom. In the twenty-first O site, O(21) is bonded in a 5-coordinate geometry to one Sr(10), one Sr(11), one Sr(12), one Sr(8), and one Nb(4) atom. In the twenty-second O site, O(22) is bonded in a 4-coordinate geometry to one Sr(10), one Sr(12), one Sr(8), and one Nb(1) atom.
Sr6Nb2O11 crystallizes in the triclinic P1 space group. There are twelve inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(14), one O(19), one O(3), one O(4), and one O(5) atom. The Sr(1)-O(1) bond length is 2.71 Å. The Sr(1)-O(14) bond length is 2.54 Å. The Sr(1)-O(19) bond length is 2.51 Å. The Sr(1)-O(3) bond length is 2.84 Å. The Sr(1)-O(4) bond length is 2.64 Å. The Sr(1)-O(5) bond length is 2.44 Å. In the second Sr site, Sr(2) is bonded to one O(1), one O(14), one O(2), one O(3), one O(4), and one O(5) atom to form distorted SrO6 octahedra that share  a cornercorner with one Sr(10)O6 octahedra, corners with three equivalent Nb(2)O6 octahedra, and corners with three equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 12-36°. The Sr(2)-O(1) bond length is 2.45 Å. The Sr(2)-O(14) bond length is 3.03 Å. The Sr(2)-O(2) bond length is 2.43 Å. The Sr(2)-O(3) bond length is 2.45 Å. The Sr(2)-O(4) bond length is 2.58 Å. The Sr(2)-O(5) bond length is 2.43 Å. In the third Sr site, Sr(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(6), one O(7), one O(8), and one O(9) atom. The Sr(3)-O(1) bond length is 2.82 Å. The Sr(3)-O(2) bond length is 2.47 Å. The Sr(3)-O(6) bond length is 2.70 Å. The Sr(3)-O(7) bond length is 2.49 Å. The Sr(3)-O(8) bond length is 2.57 Å. The Sr(3)-O(9) bond length is 2.65 Å. In the fourth Sr site, Sr(4) is bonded to one O(10), one O(6), one O(7), one O(8), and one O(9) atom to form distorted SrO5 trigonal bipyramids that share corners with three equivalent Nb(2)O6 octahedra and corners with two equivalent Nb(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 10-40°. The Sr(4)-O(10) bond length is 2.45 Å. The Sr(4)-O(6) bond length is 2.40 Å. The Sr(4)-O(7) bond length is 2.51 Å. The Sr(4)-O(8) bond length is 2.39 Å. The Sr(4)-O(9) bond length is 2.45 Å. In the fifth Sr site, Sr(5) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(9) atom. The Sr(5)-O(1) bond length is 2.65 Å. The Sr(5)-O(2) bond length is 2.59 Å. The Sr(5)-O(4) bond length is 2.54 Å. The Sr(5)-O(5) bond length is 2.54 Å. The Sr(5)-O(6) bond length is 2.46 Å. The Sr(5)-O(9) bond length is 2.77 Å. In the sixth Sr site, Sr(6) is bonded in a 6-coordinate geometry to one O(10), one O(11), one O(12), one O(13), one O(15), and one O(16) atom. The Sr(6)-O(10) bond length is 2.68 Å. The Sr(6)-O(11) bond length is 2.56 Å. The Sr(6)-O(12) bond length is 2.70 Å. The Sr(6)-O(13) bond length is 2.77 Å. The Sr(6)-O(15) bond length is 2.67 Å. The Sr(6)-O(16) bond length is 2.44 Å. In the seventh Sr site, Sr(7) is bonded to one O(11), one O(12), one O(13), one O(15), one O(16), and one O(17) atom to form distorted SrO6 pentagonal pyramids that share corners with three equivalent Nb(4)O6 octahedra and corners with three equivalent Nb(3)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 8-34°. The Sr(7)-O(11) bond length is 2.57 Å. The Sr(7)-O(12) bond length is 2.51 Å. The Sr(7)-O(13) bond length is 2.44 Å. The Sr(7)-O(15) bond length is 2.79 Å. The Sr(7)-O(16) bond length is 2.38 Å. The Sr(7)-O(17) bond length is 2.36 Å. In the eighth Sr site, Sr(8) is bonded in a 6-coordinate geometry to one O(12), one O(17), one O(18), one O(20), one O(21), and one O(22) atom. The Sr(8)-O(12) bond length is 2.82 Å. The Sr(8)-O(17) bond length is 2.42 Å. The Sr(8)-O(18) bond length is 2.57 Å. The Sr(8)-O(20) bond length is 2.92 Å. The Sr(8)-O(21) bond length is 2.72 Å. The Sr(8)-O(22) bond length is 2.56 Å. In the ninth Sr site, Sr(9) is bonded in a 6-coordinate geometry to one O(10), one O(13), one O(15), one O(7), one O(8), and one O(9) atom. The Sr(9)-O(10) bond length is 2.57 Å. The Sr(9)-O(13) bond length is 2.72 Å. The Sr(9)-O(15) bond length is 2.72 Å. The Sr(9)-O(7) bond length is 2.59 Å. The Sr(9)-O(8) bond length is 2.48 Å. The Sr(9)-O(9) bond length is 2.68 Å. In the tenth Sr site, Sr(10) is bonded to one O(14), one O(18), one O(19), one O(20), one O(21), and one O(22) atom to form SrO6 octahedra that share  a cornercorner with one Sr(2)O6 octahedra, corners with three equivalent Nb(4)O6 octahedra, and corners with three equivalent Nb(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 21-32°. The Sr(10)-O(14) bond length is 2.73 Å. The Sr(10)-O(18) bond length is 2.37 Å. The Sr(10)-O(19) bond length is 2.46 Å. The Sr(10)-O(20) bond length is 2.43 Å. The Sr(10)-O(21) bond length is 2.43 Å. The Sr(10)-O(22) bond length is 2.59 Å. In the eleventh Sr site, Sr(11) is bonded in a 6-coordinate geometry to one O(11), one O(12), one O(16), one O(17), one O(18), and one O(21) atom. The Sr(11)-O(11) bond length is 2.56 Å. The Sr(11)-O(12) bond length is 2.66 Å. The Sr(11)-O(16) bond length is 2.68 Å. The Sr(11)-O(17) bond length is 2.67 Å. The Sr(11)-O(18) bond length is 2.62 Å. The Sr(11)-O(21) bond length is 2.59 Å. In the twelfth Sr site, Sr(12) is bonded in a 7-coordinate geometry to one O(14), one O(18), one O(19), one O(20), one O(21), one O(22), and one O(3) atom. The Sr(12)-O(14) bond length is 2.58 Å. The Sr(12)-O(18) bond length is 2.95 Å. The Sr(12)-O(19) bond length is 2.50 Å. The Sr(12)-O(20) bond length is 2.42 Å. The Sr(12)-O(21) bond length is 2.97 Å. The Sr(12)-O(22) bond length is 2.72 Å. The Sr(12)-O(3) bond length is 2.49 Å. There are four inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(14), one O(19), one O(22), one O(3), and one O(4) atom to form NbO5 trigonal bipyramids that share corners with three equivalent Sr(10)O6 octahedra and corners with three equivalent Sr(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-74°. The Nb(1)-O(14) bond length is 1.98 Å. The Nb(1)-O(19) bond length is 2.02 Å. The Nb(1)-O(22) bond length is 1.92 Å. The Nb(1)-O(3) bond length is 2.00 Å. The Nb(1)-O(4) bond length is 1.94 Å. In the second Nb site, Nb(2) is bonded to one O(1), one O(2), one O(5), one O(6), one O(8), and one O(9) atom to form NbO6 octahedra that share corners with three equivalent Sr(2)O6 octahedra and corners with three equivalent Sr(4)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 12-36°. The Nb(2)-O(1) bond length is 2.07 Å. The Nb(2)-O(2) bond length is 2.03 Å. The Nb(2)-O(5) bond length is 2.03 Å. The Nb(2)-O(6) bond length is 2.01 Å. The Nb(2)-O(8) bond length is 2.05 Å. The Nb(2)-O(9) bond length is 2.04 Å. In the third Nb site, Nb(3) is bonded to one O(10), one O(11), one O(13), one O(15), and one O(7) atom to form NbO5 trigonal bipyramids that share corners with three equivalent Sr(7)O6 pentagonal pyramids and corners with two equivalent Sr(4)O5 trigonal bipyramids. The Nb(3)-O(10) bond length is 2.03 Å. The Nb(3)-O(11) bond length is 1.96 Å. The Nb(3)-O(13) bond length is 2.00 Å. The Nb(3)-O(15) bond length is 1.93 Å. The Nb(3)-O(7) bond length is 1.97 Å. In the fourth Nb site, Nb(4) is bonded to one O(12), one O(16), one O(17), one O(18), one O(20), and one O(21) atom to form NbO6 octahedra that share corners with three equivalent Sr(10)O6 octahedra and corners with three equivalent Sr(7)O6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 21-24°. The Nb(4)-O(12) bond length is 2.03 Å. The Nb(4)-O(16) bond length is 2.02 Å. The Nb(4)-O(17) bond length is 2.03 Å. The Nb(4)-O(18) bond length is 2.06 Å. The Nb(4)-O(20) bond length is 2.02 Å. The Nb(4)-O(21) bond length is 2.03 Å. There are twenty-two inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), one Sr(2), one Sr(3), one Sr(5), and one Nb(2) atom to form distorted OSr4Nb square pyramids that share  a cornercorner with one O(9)Sr4Nb square pyramid,  an edgeedge with one O(9)Sr4Nb square pyramid, and edges with two equivalent O(2)Sr3Nb tetrahedra. In the second O site, O(2) is bonded to one Sr(2), one Sr(3), one Sr(5), and one Nb(2) atom to form a mixture of distorted corner and edge-sharing OSr3Nb tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(12), one Sr(2), and one Nb(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(5), and one Nb(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(2), one Sr(5), and one Nb(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Sr(3), one Sr(4), one Sr(5), and one Nb(2) atom. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one Sr(3), one Sr(4), one Sr(9), and one Nb(3) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Sr(3), one Sr(4), one Sr(9), and one Nb(2) atom. In the ninth O site, O(9) is bonded to one Sr(3), one Sr(4), one Sr(5), one Sr(9), and one Nb(2) atom to form distorted OSr4Nb square pyramids that share  a cornercorner with one O(1)Sr4Nb square pyramid, corners with three equivalent O(2)Sr3Nb tetrahedra,  an edgeedge with one O(1)Sr4Nb square pyramid, and  an edgeedge with one O(10)Sr3Nb tetrahedra. In the tenth O site, O(10) is bonded to one Sr(4), one Sr(6), one Sr(9), and one Nb(3) atom to form distorted OSr3Nb tetrahedra that share  a cornercorner with one O(12)Sr4Nb square pyramid,  an edgeedge with one O(9)Sr4Nb square pyramid, and  an edgeedge with one O(11)Sr3Nb trigonal pyramid. In the eleventh O site, O(11) is bonded to one Sr(11), one Sr(6), one Sr(7), and one Nb(3) atom to form distorted OSr3Nb trigonal pyramids that share  a cornercorner with one O(12)Sr4Nb square pyramid,  an edgeedge with one O(12)Sr4Nb square pyramid, and  an edgeedge with one O(10)Sr3Nb tetrahedra. In the twelfth O site, O(12) is bonded to one Sr(11), one Sr(6), one Sr(7), one Sr(8), and one Nb(4) atom to form a mixture of distorted corner and edge-sharing OSr4Nb square pyramids. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to one Sr(6), one Sr(7), one Sr(9), and one Nb(3) atom. In the fourteenth O site, O(14) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(10), one Sr(12), one Sr(2), and one Nb(1) atom. In the fifteenth O site, O(15) is bonded in a 1-coordinate geometry to one Sr(6), one Sr(7), one Sr(9), and one Nb(3) atom. In the sixteenth O site, O(16) is bonded in a 4-coordinate geometry to one Sr(11), one Sr(6), one Sr(7), and one Nb(4) atom. In the seventeenth O site, O(17) is bonded in a 4-coordinate geometry to one Sr(11), one Sr(7), one Sr(8), and one Nb(4) atom. In the eighteenth O site, O(18) is bonded in a 5-coordinate geometry to one Sr(10), one Sr(11), one Sr(12), one Sr(8), and one Nb(4) atom. In the nineteenth O site, O(19) is bonded in a distorted see-saw-like geometry to one Sr(1), one Sr(10), one Sr(12), and one Nb(1) atom. In the twentieth O site, O(20) is bonded in a 3-coordinate geometry to one Sr(10), one Sr(12), one Sr(8), and one Nb(4) atom. In the twenty-first O site, O(21) is bonded in a 5-coordinate geometry to one Sr(10), one Sr(11), one Sr(12), one Sr(8), and one Nb(4) atom. In the twenty-second O site, O(22) is bonded in a 4-coordinate geometry to one Sr(10), one Sr(12), one Sr(8), and one Nb(1) atom.