Sr2Ti6O13 crystallizes in the monoclinic C2/m space group. Sr(1) is bonded in a 11-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(3), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(7), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(5), and three equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 30°. In the third Ti site, Ti(3) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 15-17°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to four equivalent Sr(1) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Ti(1), one Ti(2), and two equivalent Ti(3) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(1), one Ti(1), and one Ti(2) atom. In the fourth O site, O(4) is bonded to one Ti(3) and three equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OTi4 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(1), one Ti(2), and one Ti(3) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to two equivalent Sr(1), one Ti(3), and two equivalent Ti(1) atoms. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Ti(3) atom.
Sr2Ti6O13 crystallizes in the monoclinic C2/m space group. Sr(1) is bonded in a 11-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(3), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. The Sr(1)-O(2) bond length is 3.08 Å. Both Sr(1)-O(1) bond lengths are 2.94 Å. Both Sr(1)-O(3) bond lengths are 2.63 Å. Both Sr(1)-O(5) bond lengths are 2.76 Å. There is one shorter (2.86 Å) and one longer (3.06 Å) Sr(1)-O(6) bond length. Both Sr(1)-O(7) bond lengths are 2.78 Å. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(7), and two equivalent O(6) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. The Ti(1)-O(1) bond length is 1.88 Å. The Ti(1)-O(2) bond length is 2.08 Å. The Ti(1)-O(3) bond length is 2.11 Å. The Ti(1)-O(7) bond length is 1.91 Å. Both Ti(1)-O(6) bond lengths are 1.96 Å. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), one O(5), and three equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 30°. The Ti(2)-O(2) bond length is 2.23 Å. The Ti(2)-O(3) bond length is 1.82 Å. The Ti(2)-O(5) bond length is 1.80 Å. There are two shorter (2.02 Å) and one longer (2.17 Å) Ti(2)-O(4) bond length. In the third Ti site, Ti(3) is bonded to one O(4), one O(5), one O(6), one O(7), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 15-17°. The Ti(3)-O(4) bond length is 2.14 Å. The Ti(3)-O(5) bond length is 2.07 Å. The Ti(3)-O(6) bond length is 2.03 Å. The Ti(3)-O(7) bond length is 1.83 Å. Both Ti(3)-O(2) bond lengths are 1.97 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to four equivalent Sr(1) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Ti(1), one Ti(2), and two equivalent Ti(3) atoms. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(1), one Ti(1), and one Ti(2) atom. In the fourth O site, O(4) is bonded to one Ti(3) and three equivalent Ti(2) atoms to form a mixture of corner and edge-sharing OTi4 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Sr(1), one Ti(2), and one Ti(3) atom. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to two equivalent Sr(1), one Ti(3), and two equivalent Ti(1) atoms. In the seventh O site, O(7) is bonded in a 2-coordinate geometry to two equivalent Sr(1), one Ti(1), and one Ti(3) atom.