Sr2YTi2AlO7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and three equivalent O(4) atoms. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. Ti(1) is bonded in a distorted rectangular see-saw-like geometry to one O(4), two equivalent O(2), and two equivalent O(3) atoms. Al(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 5-coordinate geometry to three equivalent Sr(1), one Ti(1), and one Al(1) atom. In the second O site, O(1) is bonded to two equivalent Sr(1) and two equivalent Al(1) atoms to form distorted OSr2Al2 tetrahedra that share corners with four equivalent O(2)Sr2Y2Ti2 octahedra, corners with four equivalent O(3)Sr2Y2Ti2 octahedra, and corners with two equivalent O(1)Sr2Al2 tetrahedra. The corner-sharing octahedral tilt angles range from 10-80°. In the third O site, O(2) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ti(1) atoms to form distorted OSr2Y2Ti2 octahedra that share corners with four equivalent O(2)Sr2Y2Ti2 octahedra, corners with four equivalent O(3)Sr2Y2Ti2 octahedra, corners with two equivalent O(1)Sr2Al2 tetrahedra, edges with three equivalent O(3)Sr2Y2Ti2 octahedra, faces with two equivalent O(2)Sr2Y2Ti2 octahedra, and faces with two equivalent O(3)Sr2Y2Ti2 octahedra. The corner-sharing octahedral tilt angles range from 1-69°. In the fourth O site, O(3) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ti(1) atoms to form distorted OSr2Y2Ti2 octahedra that share corners with four equivalent O(2)Sr2Y2Ti2 octahedra, corners with four equivalent O(3)Sr2Y2Ti2 octahedra, corners with two equivalent O(1)Sr2Al2 tetrahedra, edges with three equivalent O(2)Sr2Y2Ti2 octahedra, faces with two equivalent O(2)Sr2Y2Ti2 octahedra, and faces with two equivalent O(3)Sr2Y2Ti2 octahedra. The corner-sharing octahedral tilt angles range from 1-69°.
Sr2YTi2AlO7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and three equivalent O(4) atoms. The Sr(1)-O(1) bond length is 2.54 Å. There is one shorter (2.77 Å) and one longer (2.79 Å) Sr(1)-O(2) bond length. There is one shorter (2.84 Å) and one longer (2.92 Å) Sr(1)-O(3) bond length. There are a spread of Sr(1)-O(4) bond distances ranging from 2.43-3.03 Å. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. There are two shorter (2.48 Å) and two longer (2.55 Å) Y(1)-O(2) bond lengths. There are two shorter (2.51 Å) and two longer (2.57 Å) Y(1)-O(3) bond lengths. Ti(1) is bonded in a distorted rectangular see-saw-like geometry to one O(4), two equivalent O(2), and two equivalent O(3) atoms. The Ti(1)-O(4) bond length is 2.77 Å. There is one shorter (1.98 Å) and one longer (1.99 Å) Ti(1)-O(2) bond length. Both Ti(1)-O(3) bond lengths are 1.98 Å. Al(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. Both Al(1)-O(1) bond lengths are 1.82 Å. Both Al(1)-O(4) bond lengths are 1.76 Å. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 5-coordinate geometry to three equivalent Sr(1), one Ti(1), and one Al(1) atom. In the second O site, O(1) is bonded to two equivalent Sr(1) and two equivalent Al(1) atoms to form distorted OSr2Al2 tetrahedra that share corners with four equivalent O(2)Sr2Y2Ti2 octahedra, corners with four equivalent O(3)Sr2Y2Ti2 octahedra, and corners with two equivalent O(1)Sr2Al2 tetrahedra. The corner-sharing octahedral tilt angles range from 10-80°. In the third O site, O(2) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ti(1) atoms to form distorted OSr2Y2Ti2 octahedra that share corners with four equivalent O(2)Sr2Y2Ti2 octahedra, corners with four equivalent O(3)Sr2Y2Ti2 octahedra, corners with two equivalent O(1)Sr2Al2 tetrahedra, edges with three equivalent O(3)Sr2Y2Ti2 octahedra, faces with two equivalent O(2)Sr2Y2Ti2 octahedra, and faces with two equivalent O(3)Sr2Y2Ti2 octahedra. The corner-sharing octahedral tilt angles range from 1-69°. In the fourth O site, O(3) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ti(1) atoms to form distorted OSr2Y2Ti2 octahedra that share corners with four equivalent O(2)Sr2Y2Ti2 octahedra, corners with four equivalent O(3)Sr2Y2Ti2 octahedra, corners with two equivalent O(1)Sr2Al2 tetrahedra, edges with three equivalent O(2)Sr2Y2Ti2 octahedra, faces with two equivalent O(2)Sr2Y2Ti2 octahedra, and faces with two equivalent O(3)Sr2Y2Ti2 octahedra. The corner-sharing octahedral tilt angles range from 1-69°.