Sr3Ga4O9 crystallizes in the triclinic P-1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one O(6), one O(7), one O(8), and two equivalent O(3) atoms. 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), and two equivalent O(5) atoms. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(2), one O(3), one O(7), and one O(8) atom to form corner-sharing GaO4 tetrahedra. In the second Ga site, Ga(2) is bonded to one O(2), one O(4), one O(8), and one O(9) atom to form corner-sharing GaO4 tetrahedra. In the third Ga site, Ga(3) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form corner-sharing GaO4 tetrahedra. In the fourth Ga site, Ga(4) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form corner-sharing GaO4 tetrahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(3), one Ga(3), and one Ga(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sr(3), one Ga(1), and one Ga(2) atom. In the third O site, O(3) is bonded to two equivalent Sr(2), one Ga(1), and one Ga(3) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(5)Sr2Ga2 tetrahedra, corners with two equivalent O(6)Sr3Ga tetrahedra, corners with three equivalent O(8)Sr2Ga2 trigonal pyramids, corners with three equivalent O(7)Sr3Ga trigonal pyramids, and  an edgeedge with one O(3)Sr2Ga2 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Ga(2), and one Ga(4) atom. In the fifth O site, O(5) is bonded to two equivalent Sr(3), one Ga(3), and one Ga(4) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(3)Sr2Ga2 tetrahedra, corners with three equivalent O(6)Sr3Ga tetrahedra, corners with two equivalent O(7)Sr3Ga trigonal pyramids, and  an edgeedge with one O(5)Sr2Ga2 tetrahedra. In the sixth O site, O(6) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Ga(4) atom to form distorted OSr3Ga tetrahedra that share corners with two equivalent O(3)Sr2Ga2 tetrahedra, corners with three equivalent O(5)Sr2Ga2 tetrahedra, corners with three equivalent O(7)Sr3Ga trigonal pyramids, and  an edgeedge with one O(8)Sr2Ga2 trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Ga(1) atom to form distorted OSr3Ga trigonal pyramids that share corners with two equivalent O(5)Sr2Ga2 tetrahedra, corners with three equivalent O(3)Sr2Ga2 tetrahedra, corners with three equivalent O(6)Sr3Ga tetrahedra,  a cornercorner with one O(8)Sr2Ga2 trigonal pyramid, and  an edgeedge with one O(8)Sr2Ga2 trigonal pyramid. In the eighth O site, O(8) is bonded to one Sr(1), one Sr(2), one Ga(1), and one Ga(2) atom to form distorted OSr2Ga2 trigonal pyramids that share corners with three equivalent O(3)Sr2Ga2 tetrahedra,  a cornercorner with one O(7)Sr3Ga trigonal pyramid,  an edgeedge with one O(6)Sr3Ga tetrahedra, and  an edgeedge with one O(7)Sr3Ga trigonal pyramid. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Sr(1), one Ga(2), and one Ga(3) atom.
Sr3Ga4O9 crystallizes in the triclinic P-1 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), one O(6), one O(7), one O(8), and one O(9) atom. The Sr(1)-O(1) bond length is 2.64 Å. The Sr(1)-O(4) bond length is 2.52 Å. The Sr(1)-O(6) bond length is 2.54 Å. The Sr(1)-O(7) bond length is 2.67 Å. The Sr(1)-O(8) bond length is 2.55 Å. The Sr(1)-O(9) bond length is 2.45 Å. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one O(6), one O(7), one O(8), and two equivalent O(3) atoms. The Sr(2)-O(6) bond length is 2.55 Å. The Sr(2)-O(7) bond length is 2.40 Å. The Sr(2)-O(8) bond length is 2.65 Å. There is one shorter (2.53 Å) and one longer (2.56 Å) Sr(2)-O(3) bond length. 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), and two equivalent O(5) atoms. The Sr(3)-O(1) bond length is 2.63 Å. The Sr(3)-O(2) bond length is 2.45 Å. The Sr(3)-O(6) bond length is 2.51 Å. The Sr(3)-O(7) bond length is 2.52 Å. There is one shorter (2.62 Å) and one longer (2.72 Å) Sr(3)-O(5) bond length. There are four inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one O(2), one O(3), one O(7), and one O(8) atom to form corner-sharing GaO4 tetrahedra. The Ga(1)-O(2) bond length is 1.84 Å. The Ga(1)-O(3) bond length is 1.89 Å. The Ga(1)-O(7) bond length is 1.81 Å. The Ga(1)-O(8) bond length is 1.90 Å. In the second Ga site, Ga(2) is bonded to one O(2), one O(4), one O(8), and one O(9) atom to form corner-sharing GaO4 tetrahedra. The Ga(2)-O(2) bond length is 1.84 Å. The Ga(2)-O(4) bond length is 1.85 Å. The Ga(2)-O(8) bond length is 1.86 Å. The Ga(2)-O(9) bond length is 1.84 Å. In the third Ga site, Ga(3) is bonded to one O(1), one O(3), one O(5), and one O(9) atom to form corner-sharing GaO4 tetrahedra. The Ga(3)-O(1) bond length is 1.85 Å. The Ga(3)-O(3) bond length is 1.87 Å. The Ga(3)-O(5) bond length is 1.84 Å. The Ga(3)-O(9) bond length is 1.85 Å. In the fourth Ga site, Ga(4) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form corner-sharing GaO4 tetrahedra. The Ga(4)-O(1) bond length is 1.85 Å. The Ga(4)-O(4) bond length is 1.86 Å. The Ga(4)-O(5) bond length is 1.89 Å. The Ga(4)-O(6) bond length is 1.81 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Sr(1), one Sr(3), one Ga(3), and one Ga(4) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Sr(3), one Ga(1), and one Ga(2) atom. In the third O site, O(3) is bonded to two equivalent Sr(2), one Ga(1), and one Ga(3) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(5)Sr2Ga2 tetrahedra, corners with two equivalent O(6)Sr3Ga tetrahedra, corners with three equivalent O(8)Sr2Ga2 trigonal pyramids, corners with three equivalent O(7)Sr3Ga trigonal pyramids, and  an edgeedge with one O(3)Sr2Ga2 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Sr(1), one Ga(2), and one Ga(4) atom. In the fifth O site, O(5) is bonded to two equivalent Sr(3), one Ga(3), and one Ga(4) atom to form distorted OSr2Ga2 tetrahedra that share  a cornercorner with one O(3)Sr2Ga2 tetrahedra, corners with three equivalent O(6)Sr3Ga tetrahedra, corners with two equivalent O(7)Sr3Ga trigonal pyramids, and  an edgeedge with one O(5)Sr2Ga2 tetrahedra. In the sixth O site, O(6) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Ga(4) atom to form distorted OSr3Ga tetrahedra that share corners with two equivalent O(3)Sr2Ga2 tetrahedra, corners with three equivalent O(5)Sr2Ga2 tetrahedra, corners with three equivalent O(7)Sr3Ga trigonal pyramids, and  an edgeedge with one O(8)Sr2Ga2 trigonal pyramid. In the seventh O site, O(7) is bonded to one Sr(1), one Sr(2), one Sr(3), and one Ga(1) atom to form distorted OSr3Ga trigonal pyramids that share corners with two equivalent O(5)Sr2Ga2 tetrahedra, corners with three equivalent O(3)Sr2Ga2 tetrahedra, corners with three equivalent O(6)Sr3Ga tetrahedra,  a cornercorner with one O(8)Sr2Ga2 trigonal pyramid, and  an edgeedge with one O(8)Sr2Ga2 trigonal pyramid. In the eighth O site, O(8) is bonded to one Sr(1), one Sr(2), one Ga(1), and one Ga(2) atom to form distorted OSr2Ga2 trigonal pyramids that share corners with three equivalent O(3)Sr2Ga2 tetrahedra,  a cornercorner with one O(7)Sr3Ga trigonal pyramid,  an edgeedge with one O(6)Sr3Ga tetrahedra, and  an edgeedge with one O(7)Sr3Ga trigonal pyramid. In the ninth O site, O(9) is bonded in a 3-coordinate geometry to one Sr(1), one Ga(2), and one Ga(3) atom.