Sr2Ti6N2O11 crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to one O(4), one O(8), two equivalent O(10), two equivalent O(11), two equivalent O(2), and two equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to two equivalent N(2), two equivalent O(1), and two equivalent O(9) atoms. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one N(1), one O(1), one O(11), one O(3), and two equivalent O(4) atoms to form TiNO5 octahedra that share  a cornercorner with one Ti(3)O6 octahedra, corners with two equivalent Ti(1)NO5 octahedra,  an edgeedge with one Ti(2)NO5 octahedra, and edges with two equivalent Ti(4)N3O3 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. In the second Ti site, Ti(2) is bonded to one N(1), one O(1), one O(2), one O(7), and two equivalent O(5) atoms to form distorted TiNO5 octahedra that share corners with two equivalent Ti(2)NO5 octahedra,  an edgeedge with one Ti(1)NO5 octahedra,  an edgeedge with one Ti(3)O6 octahedra, edges with two equivalent Ti(4)N3O3 octahedra, and edges with two equivalent Ti(5)O6 octahedra. The corner-sharing octahedral tilt angles are 26°. In the third Ti site, Ti(3) is bonded to one O(2), one O(3), one O(7), one O(8), and two equivalent O(6) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Ti(1)NO5 octahedra, corners with two equivalent Ti(3)O6 octahedra,  an edgeedge with one Ti(2)NO5 octahedra, and edges with two equivalent Ti(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-25°. In the fourth Ti site, Ti(4) is bonded to one N(2), two equivalent N(1), one O(4), one O(5), and one O(9) atom to form distorted TiN3O3 octahedra that share corners with two equivalent Ti(4)N3O3 octahedra,  an edgeedge with one Ti(5)O6 octahedra, edges with two equivalent Ti(1)NO5 octahedra, and edges with two equivalent Ti(2)NO5 octahedra. The corner-sharing octahedral tilt angles are 30°. In the fifth Ti site, Ti(5) is bonded to one O(10), one O(5), one O(6), one O(9), and two equivalent O(7) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(5)O6 octahedra,  an edgeedge with one Ti(4)N3O3 octahedra, edges with two equivalent Ti(2)NO5 octahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles are 32°. In the sixth Ti site, Ti(6) is bonded in a 6-coordinate geometry to one N(2), one O(10), one O(11), one O(6), and two equivalent O(8) atoms. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Ti(1), one Ti(2), and two equivalent Ti(4) atoms to form distorted NTi4 trigonal pyramids that share  a cornercorner with one O(7)Ti4 trigonal pyramid, corners with two equivalent N(1)Ti4 trigonal pyramids,  an edgeedge with one O(1)Sr2Ti2 tetrahedra, and edges with two equivalent O(5)Ti4 trigonal pyramids. In the second N site, N(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(2), one Ti(4), and one Ti(6) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(2), one Ti(1), and one Ti(2) atom to form distorted OSr2Ti2 tetrahedra that share corners with two equivalent O(1)Sr2Ti2 tetrahedra,  a cornercorner with one O(7)Ti4 trigonal pyramid, corners with two equivalent O(5)Ti4 trigonal pyramids, and  an edgeedge with one N(1)Ti4 trigonal pyramid. In the second O site, O(2) is bonded in a distorted water-like geometry to two equivalent Sr(1), one Ti(2), and one Ti(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Ti(3) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Sr(1), one Ti(4), and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded to one Ti(4), one Ti(5), and two equivalent Ti(2) atoms to form distorted OTi4 trigonal pyramids that share corners with two equivalent O(1)Sr2Ti2 tetrahedra,  a cornercorner with one O(10)Sr2Ti2 trigonal pyramid,  a cornercorner with one O(6)Ti4 trigonal pyramid, corners with two equivalent O(5)Ti4 trigonal pyramids, edges with two equivalent N(1)Ti4 trigonal pyramids, and edges with two equivalent O(7)Ti4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Ti(5), one Ti(6), and two equivalent Ti(3) atoms to form distorted OTi4 trigonal pyramids that share  a cornercorner with one O(5)Ti4 trigonal pyramid, corners with two equivalent O(6)Ti4 trigonal pyramids,  an edgeedge with one O(10)Sr2Ti2 trigonal pyramid, and edges with two equivalent O(7)Ti4 trigonal pyramids. In the seventh O site, O(7) is bonded to one Ti(2), one Ti(3), and two equivalent Ti(5) atoms to form distorted OTi4 trigonal pyramids that share  a cornercorner with one O(1)Sr2Ti2 tetrahedra,  a cornercorner with one N(1)Ti4 trigonal pyramid, corners with two equivalent O(10)Sr2Ti2 trigonal pyramids, corners with two equivalent O(7)Ti4 trigonal pyramids, edges with two equivalent O(5)Ti4 trigonal pyramids, and edges with two equivalent O(6)Ti4 trigonal pyramids. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1), one Ti(3), and two equivalent Ti(6) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(2), one Ti(4), and one Ti(5) atom. In the tenth O site, O(10) is bonded to two equivalent Sr(1), one Ti(5), and one Ti(6) atom to form distorted OSr2Ti2 trigonal pyramids that share  a cornercorner with one O(5)Ti4 trigonal pyramid, corners with two equivalent O(10)Sr2Ti2 trigonal pyramids, corners with two equivalent O(7)Ti4 trigonal pyramids, and  an edgeedge with one O(6)Ti4 trigonal pyramid. In the eleventh O site, O(11) is bonded in a distorted linear geometry to two equivalent Sr(1), one Ti(1), and one Ti(6) atom.
Sr2Ti6N2O11 crystallizes in the monoclinic Cm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 10-coordinate geometry to one O(4), one O(8), two equivalent O(10), two equivalent O(11), two equivalent O(2), and two equivalent O(3) atoms. The Sr(1)-O(4) bond length is 3.14 Å. The Sr(1)-O(8) bond length is 3.04 Å. Both Sr(1)-O(10) bond lengths are 2.55 Å. Both Sr(1)-O(11) bond lengths are 2.91 Å. Both Sr(1)-O(2) bond lengths are 2.87 Å. Both Sr(1)-O(3) bond lengths are 2.79 Å. In the second Sr site, Sr(2) is bonded in a 6-coordinate geometry to two equivalent N(2), two equivalent O(1), and two equivalent O(9) atoms. Both Sr(2)-N(2) bond lengths are 2.73 Å. Both Sr(2)-O(1) bond lengths are 2.59 Å. Both Sr(2)-O(9) bond lengths are 2.72 Å. There are six inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one N(1), one O(1), one O(11), one O(3), and two equivalent O(4) atoms to form TiNO5 octahedra that share  a cornercorner with one Ti(3)O6 octahedra, corners with two equivalent Ti(1)NO5 octahedra,  an edgeedge with one Ti(2)NO5 octahedra, and edges with two equivalent Ti(4)N3O3 octahedra. The corner-sharing octahedral tilt angles range from 10-17°. The Ti(1)-N(1) bond length is 1.99 Å. The Ti(1)-O(1) bond length is 2.13 Å. The Ti(1)-O(11) bond length is 1.95 Å. The Ti(1)-O(3) bond length is 1.99 Å. Both Ti(1)-O(4) bond lengths are 1.93 Å. In the second Ti site, Ti(2) is bonded to one N(1), one O(1), one O(2), one O(7), and two equivalent O(5) atoms to form distorted TiNO5 octahedra that share corners with two equivalent Ti(2)NO5 octahedra,  an edgeedge with one Ti(1)NO5 octahedra,  an edgeedge with one Ti(3)O6 octahedra, edges with two equivalent Ti(4)N3O3 octahedra, and edges with two equivalent Ti(5)O6 octahedra. The corner-sharing octahedral tilt angles are 26°. The Ti(2)-N(1) bond length is 2.09 Å. The Ti(2)-O(1) bond length is 1.85 Å. The Ti(2)-O(2) bond length is 1.95 Å. The Ti(2)-O(7) bond length is 2.23 Å. Both Ti(2)-O(5) bond lengths are 1.98 Å. In the third Ti site, Ti(3) is bonded to one O(2), one O(3), one O(7), one O(8), and two equivalent O(6) atoms to form distorted TiO6 octahedra that share  a cornercorner with one Ti(1)NO5 octahedra, corners with two equivalent Ti(3)O6 octahedra,  an edgeedge with one Ti(2)NO5 octahedra, and edges with two equivalent Ti(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 17-25°. The Ti(3)-O(2) bond length is 1.91 Å. The Ti(3)-O(3) bond length is 1.81 Å. The Ti(3)-O(7) bond length is 2.20 Å. The Ti(3)-O(8) bond length is 2.07 Å. Both Ti(3)-O(6) bond lengths are 1.98 Å. In the fourth Ti site, Ti(4) is bonded to one N(2), two equivalent N(1), one O(4), one O(5), and one O(9) atom to form distorted TiN3O3 octahedra that share corners with two equivalent Ti(4)N3O3 octahedra,  an edgeedge with one Ti(5)O6 octahedra, edges with two equivalent Ti(1)NO5 octahedra, and edges with two equivalent Ti(2)NO5 octahedra. The corner-sharing octahedral tilt angles are 30°. The Ti(4)-N(2) bond length is 1.84 Å. Both Ti(4)-N(1) bond lengths are 1.99 Å. The Ti(4)-O(4) bond length is 2.12 Å. The Ti(4)-O(5) bond length is 2.29 Å. The Ti(4)-O(9) bond length is 2.02 Å. In the fifth Ti site, Ti(5) is bonded to one O(10), one O(5), one O(6), one O(9), and two equivalent O(7) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(5)O6 octahedra,  an edgeedge with one Ti(4)N3O3 octahedra, edges with two equivalent Ti(2)NO5 octahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles are 32°. The Ti(5)-O(10) bond length is 1.79 Å. The Ti(5)-O(5) bond length is 2.25 Å. The Ti(5)-O(6) bond length is 2.26 Å. The Ti(5)-O(9) bond length is 1.84 Å. Both Ti(5)-O(7) bond lengths are 2.00 Å. In the sixth Ti site, Ti(6) is bonded in a 6-coordinate geometry to one N(2), one O(10), one O(11), one O(6), and two equivalent O(8) atoms. The Ti(6)-N(2) bond length is 1.82 Å. The Ti(6)-O(10) bond length is 2.44 Å. The Ti(6)-O(11) bond length is 1.87 Å. The Ti(6)-O(6) bond length is 2.16 Å. Both Ti(6)-O(8) bond lengths are 1.98 Å. There are two inequivalent N sites. In the first N site, N(1) is bonded to one Ti(1), one Ti(2), and two equivalent Ti(4) atoms to form distorted NTi4 trigonal pyramids that share  a cornercorner with one O(7)Ti4 trigonal pyramid, corners with two equivalent N(1)Ti4 trigonal pyramids,  an edgeedge with one O(1)Sr2Ti2 tetrahedra, and edges with two equivalent O(5)Ti4 trigonal pyramids. In the second N site, N(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(2), one Ti(4), and one Ti(6) atom. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(2), one Ti(1), and one Ti(2) atom to form distorted OSr2Ti2 tetrahedra that share corners with two equivalent O(1)Sr2Ti2 tetrahedra,  a cornercorner with one O(7)Ti4 trigonal pyramid, corners with two equivalent O(5)Ti4 trigonal pyramids, and  an edgeedge with one N(1)Ti4 trigonal pyramid. In the second O site, O(2) is bonded in a distorted water-like geometry to two equivalent Sr(1), one Ti(2), and one Ti(3) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Ti(3) atom. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Sr(1), one Ti(4), and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded to one Ti(4), one Ti(5), and two equivalent Ti(2) atoms to form distorted OTi4 trigonal pyramids that share corners with two equivalent O(1)Sr2Ti2 tetrahedra,  a cornercorner with one O(10)Sr2Ti2 trigonal pyramid,  a cornercorner with one O(6)Ti4 trigonal pyramid, corners with two equivalent O(5)Ti4 trigonal pyramids, edges with two equivalent N(1)Ti4 trigonal pyramids, and edges with two equivalent O(7)Ti4 trigonal pyramids. In the sixth O site, O(6) is bonded to one Ti(5), one Ti(6), and two equivalent Ti(3) atoms to form distorted OTi4 trigonal pyramids that share  a cornercorner with one O(5)Ti4 trigonal pyramid, corners with two equivalent O(6)Ti4 trigonal pyramids,  an edgeedge with one O(10)Sr2Ti2 trigonal pyramid, and edges with two equivalent O(7)Ti4 trigonal pyramids. In the seventh O site, O(7) is bonded to one Ti(2), one Ti(3), and two equivalent Ti(5) atoms to form distorted OTi4 trigonal pyramids that share  a cornercorner with one O(1)Sr2Ti2 tetrahedra,  a cornercorner with one N(1)Ti4 trigonal pyramid, corners with two equivalent O(10)Sr2Ti2 trigonal pyramids, corners with two equivalent O(7)Ti4 trigonal pyramids, edges with two equivalent O(5)Ti4 trigonal pyramids, and edges with two equivalent O(6)Ti4 trigonal pyramids. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Sr(1), one Ti(3), and two equivalent Ti(6) atoms. In the ninth O site, O(9) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(2), one Ti(4), and one Ti(5) atom. In the tenth O site, O(10) is bonded to two equivalent Sr(1), one Ti(5), and one Ti(6) atom to form distorted OSr2Ti2 trigonal pyramids that share  a cornercorner with one O(5)Ti4 trigonal pyramid, corners with two equivalent O(10)Sr2Ti2 trigonal pyramids, corners with two equivalent O(7)Ti4 trigonal pyramids, and  an edgeedge with one O(6)Ti4 trigonal pyramid. In the eleventh O site, O(11) is bonded in a distorted linear geometry to two equivalent Sr(1), one Ti(1), and one Ti(6) atom.