Sr2Ti2GaAlO7 crystallizes in the triclinic P1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(1), one O(14), one O(3), one O(7), two equivalent O(11), and two equivalent O(12) atoms. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one O(2), one O(6), one O(8), two equivalent O(10), and two equivalent O(4) atoms. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one O(13), one O(14), one O(2), one O(3), two equivalent O(11), and two equivalent O(12) atoms. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(6), one O(7), one O(8), two equivalent O(10), and two equivalent O(4) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(8), and one O(9) atom. In the second Ti site, Ti(2) is bonded in a 4-coordinate geometry to one O(1), one O(13), one O(14), and one O(3) atom. In the third Ti site, Ti(3) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(8), and one O(9) atom. In the fourth Ti site, Ti(4) is bonded in a 4-coordinate geometry to one O(1), one O(13), one O(14), and one O(3) atom. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(10), one O(11), one O(2), and one O(7) atom to form corner-sharing GaO4 tetrahedra. In the second Ga site, Ga(2) is bonded to one O(12), one O(2), one O(4), and one O(7) atom to form corner-sharing GaO4 tetrahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a distorted T-shaped geometry to one O(13), one O(5), and one O(9) atom. In the second Al site, Al(2) is bonded in a distorted T-shaped geometry to one O(1), one O(5), and one O(9) atom. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Ti(2), one Ti(4), and one Al(2) atom. In the second O site, O(2) is bonded to one Sr(2), one Sr(3), one Ga(1), and one Ga(2) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(8)Sr2Ti2 tetrahedra and corners with two equivalent O(7)Sr2Ga2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Ti(2), and one Ti(4) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Sr(2), two equivalent Sr(4), and one Ga(2) atom. In the fifth O site, O(5) is bonded in a see-saw-like geometry to one Ti(1), one Ti(3), one Al(1), and one Al(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Sr(2), one Sr(4), one Ti(1), and one Ti(3) atom. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(4), one Ga(1), and one Ga(2) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(8)Sr2Ti2 tetrahedra and corners with two equivalent O(2)Sr2Ga2 tetrahedra. In the eighth O site, O(8) is bonded to one Sr(2), one Sr(4), one Ti(1), and one Ti(3) atom to form distorted corner-sharing OSr2Ti2 tetrahedra. In the ninth O site, O(9) is bonded in a see-saw-like geometry to one Ti(1), one Ti(3), one Al(1), and one Al(2) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to two equivalent Sr(2), two equivalent Sr(4), and one Ga(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), and one Ga(1) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), and one Ga(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Sr(3), one Ti(2), one Ti(4), and one Al(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Ti(2), and one Ti(4) atom.
Sr2Ti2GaAlO7 crystallizes in the triclinic P1 space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to one O(1), one O(14), one O(3), one O(7), two equivalent O(11), and two equivalent O(12) atoms. The Sr(1)-O(1) bond length is 2.93 Å. The Sr(1)-O(14) bond length is 2.57 Å. The Sr(1)-O(3) bond length is 2.65 Å. The Sr(1)-O(7) bond length is 2.47 Å. There is one shorter (2.51 Å) and one longer (2.97 Å) Sr(1)-O(11) bond length. There is one shorter (2.58 Å) and one longer (2.74 Å) Sr(1)-O(12) bond length. In the second Sr site, Sr(2) is bonded in a 7-coordinate geometry to one O(2), one O(6), one O(8), two equivalent O(10), and two equivalent O(4) atoms. The Sr(2)-O(2) bond length is 2.42 Å. The Sr(2)-O(6) bond length is 2.68 Å. The Sr(2)-O(8) bond length is 2.60 Å. There is one shorter (2.58 Å) and one longer (2.73 Å) Sr(2)-O(10) bond length. There is one shorter (2.52 Å) and one longer (2.95 Å) Sr(2)-O(4) bond length. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to one O(13), one O(14), one O(2), one O(3), two equivalent O(11), and two equivalent O(12) atoms. The Sr(3)-O(13) bond length is 3.16 Å. The Sr(3)-O(14) bond length is 2.65 Å. The Sr(3)-O(2) bond length is 2.49 Å. The Sr(3)-O(3) bond length is 2.53 Å. There is one shorter (2.60 Å) and one longer (2.70 Å) Sr(3)-O(11) bond length. There is one shorter (2.55 Å) and one longer (2.93 Å) Sr(3)-O(12) bond length. In the fourth Sr site, Sr(4) is bonded in a 7-coordinate geometry to one O(6), one O(7), one O(8), two equivalent O(10), and two equivalent O(4) atoms. The Sr(4)-O(6) bond length is 2.68 Å. The Sr(4)-O(7) bond length is 2.46 Å. The Sr(4)-O(8) bond length is 2.60 Å. There is one shorter (2.52 Å) and one longer (2.95 Å) Sr(4)-O(10) bond length. There is one shorter (2.56 Å) and one longer (2.72 Å) Sr(4)-O(4) bond length. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(8), and one O(9) atom. The Ti(1)-O(5) bond length is 2.16 Å. The Ti(1)-O(6) bond length is 1.90 Å. The Ti(1)-O(8) bond length is 1.87 Å. The Ti(1)-O(9) bond length is 2.16 Å. In the second Ti site, Ti(2) is bonded in a 4-coordinate geometry to one O(1), one O(13), one O(14), and one O(3) atom. The Ti(2)-O(1) bond length is 2.29 Å. The Ti(2)-O(13) bond length is 1.97 Å. The Ti(2)-O(14) bond length is 1.85 Å. The Ti(2)-O(3) bond length is 1.92 Å. In the third Ti site, Ti(3) is bonded in a 4-coordinate geometry to one O(5), one O(6), one O(8), and one O(9) atom. The Ti(3)-O(5) bond length is 2.18 Å. The Ti(3)-O(6) bond length is 1.87 Å. The Ti(3)-O(8) bond length is 1.89 Å. The Ti(3)-O(9) bond length is 2.16 Å. In the fourth Ti site, Ti(4) is bonded in a 4-coordinate geometry to one O(1), one O(13), one O(14), and one O(3) atom. The Ti(4)-O(1) bond length is 1.98 Å. The Ti(4)-O(13) bond length is 2.27 Å. The Ti(4)-O(14) bond length is 1.92 Å. The Ti(4)-O(3) bond length is 1.83 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(10), one O(11), one O(2), and one O(7) atom to form corner-sharing GaO4 tetrahedra. The Ga(1)-O(10) bond length is 1.87 Å. The Ga(1)-O(11) bond length is 1.85 Å. The Ga(1)-O(2) bond length is 1.92 Å. The Ga(1)-O(7) bond length is 1.91 Å. In the second Ga site, Ga(2) is bonded to one O(12), one O(2), one O(4), and one O(7) atom to form corner-sharing GaO4 tetrahedra. The Ga(2)-O(12) bond length is 1.86 Å. The Ga(2)-O(2) bond length is 1.92 Å. The Ga(2)-O(4) bond length is 1.86 Å. The Ga(2)-O(7) bond length is 1.92 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a distorted T-shaped geometry to one O(13), one O(5), and one O(9) atom. The Al(1)-O(13) bond length is 1.81 Å. The Al(1)-O(5) bond length is 1.89 Å. The Al(1)-O(9) bond length is 1.92 Å. In the second Al site, Al(2) is bonded in a distorted T-shaped geometry to one O(1), one O(5), and one O(9) atom. The Al(2)-O(1) bond length is 1.82 Å. The Al(2)-O(5) bond length is 1.94 Å. The Al(2)-O(9) bond length is 1.92 Å. There are fourteen inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Sr(1), one Ti(2), one Ti(4), and one Al(2) atom. In the second O site, O(2) is bonded to one Sr(2), one Sr(3), one Ga(1), and one Ga(2) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(8)Sr2Ti2 tetrahedra and corners with two equivalent O(7)Sr2Ga2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Ti(2), and one Ti(4) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to two equivalent Sr(2), two equivalent Sr(4), and one Ga(2) atom. In the fifth O site, O(5) is bonded in a see-saw-like geometry to one Ti(1), one Ti(3), one Al(1), and one Al(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Sr(2), one Sr(4), one Ti(1), and one Ti(3) atom. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(4), one Ga(1), and one Ga(2) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(8)Sr2Ti2 tetrahedra and corners with two equivalent O(2)Sr2Ga2 tetrahedra. In the eighth O site, O(8) is bonded to one Sr(2), one Sr(4), one Ti(1), and one Ti(3) atom to form distorted corner-sharing OSr2Ti2 tetrahedra. In the ninth O site, O(9) is bonded in a see-saw-like geometry to one Ti(1), one Ti(3), one Al(1), and one Al(2) atom. In the tenth O site, O(10) is bonded in a 5-coordinate geometry to two equivalent Sr(2), two equivalent Sr(4), and one Ga(1) atom. In the eleventh O site, O(11) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), and one Ga(1) atom. In the twelfth O site, O(12) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), and one Ga(2) atom. In the thirteenth O site, O(13) is bonded in a 3-coordinate geometry to one Sr(3), one Ti(2), one Ti(4), and one Al(1) atom. In the fourteenth O site, O(14) is bonded in a 4-coordinate geometry to one Sr(1), one Sr(3), one Ti(2), and one Ti(4) atom.