CaYGa3O7 crystallizes in the orthorhombic Cmm2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(3), one O(5), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. Y(1) is bonded in a 8-coordinate geometry to one O(4), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing GaO4 tetrahedra. In the second Ga site, Ga(2) is bonded to one O(3), one O(6), and two equivalent O(1) atoms to form distorted corner-sharing GaO4 trigonal pyramids. In the third Ga site, Ga(3) is bonded to one O(4), one O(5), and two equivalent O(2) atoms to form distorted corner-sharing GaO4 tetrahedra. There are six inequivalent O sites. In the first O site, O(5) is bonded to two equivalent Ca(1) and two equivalent Ga(3) atoms to form distorted OCa2Ga2 tetrahedra that share corners with two equivalent O(4)Ca2YGa tetrahedra, corners with two equivalent O(3)CaY2Ga tetrahedra, and edges with two equivalent O(4)Ca2YGa tetrahedra. In the second O site, O(6) is bonded to two equivalent Y(1) and two equivalent Ga(2) atoms to form OY2Ga2 tetrahedra that share corners with two equivalent O(4)Ca2YGa tetrahedra, corners with two equivalent O(3)CaY2Ga tetrahedra, and edges with two equivalent O(3)CaY2Ga tetrahedra. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Y(1), one Ga(1), and one Ga(2) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Y(1), one Ga(1), and one Ga(3) atom. In the fifth O site, O(3) is bonded to one Ca(1), two equivalent Y(1), and one Ga(2) atom to form OCaY2Ga tetrahedra that share  a cornercorner with one O(5)Ca2Ga2 tetrahedra,  a cornercorner with one O(6)Y2Ga2 tetrahedra, corners with four equivalent O(4)Ca2YGa tetrahedra,  an edgeedge with one O(3)CaY2Ga tetrahedra, and  an edgeedge with one O(6)Y2Ga2 tetrahedra. In the sixth O site, O(4) is bonded to two equivalent Ca(1), one Y(1), and one Ga(3) atom to form distorted OCa2YGa tetrahedra that share  a cornercorner with one O(5)Ca2Ga2 tetrahedra,  a cornercorner with one O(6)Y2Ga2 tetrahedra, corners with four equivalent O(3)CaY2Ga tetrahedra,  an edgeedge with one O(5)Ca2Ga2 tetrahedra, and  an edgeedge with one O(4)Ca2YGa tetrahedra.
CaYGa3O7 crystallizes in the orthorhombic Cmm2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(3), one O(5), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. The Ca(1)-O(3) bond length is 2.59 Å. The Ca(1)-O(5) bond length is 2.45 Å. Both Ca(1)-O(1) bond lengths are 2.43 Å. Both Ca(1)-O(2) bond lengths are 2.98 Å. Both Ca(1)-O(4) bond lengths are 2.65 Å. Y(1) is bonded in a 8-coordinate geometry to one O(4), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Y(1)-O(4) bond length is 2.35 Å. The Y(1)-O(6) bond length is 2.38 Å. Both Y(1)-O(1) bond lengths are 2.90 Å. Both Y(1)-O(2) bond lengths are 2.34 Å. Both Y(1)-O(3) bond lengths are 2.48 Å. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form corner-sharing GaO4 tetrahedra. Both Ga(1)-O(1) bond lengths are 1.84 Å. Both Ga(1)-O(2) bond lengths are 1.86 Å. In the second Ga site, Ga(2) is bonded to one O(3), one O(6), and two equivalent O(1) atoms to form distorted corner-sharing GaO4 trigonal pyramids. The Ga(2)-O(3) bond length is 1.82 Å. The Ga(2)-O(6) bond length is 1.88 Å. Both Ga(2)-O(1) bond lengths are 1.86 Å. In the third Ga site, Ga(3) is bonded to one O(4), one O(5), and two equivalent O(2) atoms to form distorted corner-sharing GaO4 tetrahedra. The Ga(3)-O(4) bond length is 1.81 Å. The Ga(3)-O(5) bond length is 1.85 Å. Both Ga(3)-O(2) bond lengths are 1.88 Å. There are six inequivalent O sites. In the first O site, O(5) is bonded to two equivalent Ca(1) and two equivalent Ga(3) atoms to form distorted OCa2Ga2 tetrahedra that share corners with two equivalent O(4)Ca2YGa tetrahedra, corners with two equivalent O(3)CaY2Ga tetrahedra, and edges with two equivalent O(4)Ca2YGa tetrahedra. In the second O site, O(6) is bonded to two equivalent Y(1) and two equivalent Ga(2) atoms to form OY2Ga2 tetrahedra that share corners with two equivalent O(4)Ca2YGa tetrahedra, corners with two equivalent O(3)CaY2Ga tetrahedra, and edges with two equivalent O(3)CaY2Ga tetrahedra. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Y(1), one Ga(1), and one Ga(2) atom. In the fourth O site, O(2) is bonded in a 3-coordinate geometry to one Ca(1), one Y(1), one Ga(1), and one Ga(3) atom. In the fifth O site, O(3) is bonded to one Ca(1), two equivalent Y(1), and one Ga(2) atom to form OCaY2Ga tetrahedra that share  a cornercorner with one O(5)Ca2Ga2 tetrahedra,  a cornercorner with one O(6)Y2Ga2 tetrahedra, corners with four equivalent O(4)Ca2YGa tetrahedra,  an edgeedge with one O(3)CaY2Ga tetrahedra, and  an edgeedge with one O(6)Y2Ga2 tetrahedra. In the sixth O site, O(4) is bonded to two equivalent Ca(1), one Y(1), and one Ga(3) atom to form distorted OCa2YGa tetrahedra that share  a cornercorner with one O(5)Ca2Ga2 tetrahedra,  a cornercorner with one O(6)Y2Ga2 tetrahedra, corners with four equivalent O(3)CaY2Ga tetrahedra,  an edgeedge with one O(5)Ca2Ga2 tetrahedra, and  an edgeedge with one O(4)Ca2YGa tetrahedra.