Gd3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Ga(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form GaO4 tetrahedra that share  a cornercorner with one Gd(1)O7 pentagonal bipyramid and  an edgeedge with one Gd(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Gd(1), two equivalent Gd(2), and one Ga(1) atom to form distorted OGd3Ga tetrahedra that share corners with eight equivalent O(3)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Ga trigonal pyramids, and edges with two equivalent O(4)Gd3Ga trigonal pyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to four equivalent Gd(2) and one Ga(1) atom. In the third O site, O(3) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(3)Gd4 tetrahedra, corners with four equivalent O(1)Gd3Ga tetrahedra, corners with six equivalent O(4)Gd3Ga trigonal pyramids, edges with three equivalent O(3)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Ga trigonal pyramid. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one Ga(1) atom to form distorted OGd3Ga trigonal pyramids that share corners with two equivalent O(1)Gd3Ga tetrahedra, corners with six equivalent O(3)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Ga trigonal pyramids,  an edgeedge with one O(1)Gd3Ga tetrahedra,  an edgeedge with one O(3)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Ga trigonal pyramid.
Gd3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Gd sites. In the first Gd site, Gd(1) is bonded to one O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted GdO7 pentagonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Gd(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. The Gd(1)-O(1) bond length is 2.44 Å. Both Gd(1)-O(4) bond lengths are 2.47 Å. There are two shorter (2.30 Å) and two longer (2.32 Å) Gd(1)-O(3) bond lengths. In the second Gd site, Gd(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Gd(2)-O(1) bond length is 2.40 Å. There is one shorter (2.56 Å) and one longer (2.61 Å) Gd(2)-O(2) bond length. There is one shorter (2.24 Å) and one longer (2.27 Å) Gd(2)-O(3) bond length. There is one shorter (2.31 Å) and one longer (2.41 Å) Gd(2)-O(4) bond length. Ga(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form GaO4 tetrahedra that share  a cornercorner with one Gd(1)O7 pentagonal bipyramid and  an edgeedge with one Gd(1)O7 pentagonal bipyramid. The Ga(1)-O(1) bond length is 1.84 Å. The Ga(1)-O(2) bond length is 1.88 Å. Both Ga(1)-O(4) bond lengths are 1.87 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Gd(1), two equivalent Gd(2), and one Ga(1) atom to form distorted OGd3Ga tetrahedra that share corners with eight equivalent O(3)Gd4 tetrahedra, corners with four equivalent O(4)Gd3Ga trigonal pyramids, and edges with two equivalent O(4)Gd3Ga trigonal pyramids. In the second O site, O(2) is bonded in a 5-coordinate geometry to four equivalent Gd(2) and one Ga(1) atom. In the third O site, O(3) is bonded to two equivalent Gd(1) and two equivalent Gd(2) atoms to form OGd4 tetrahedra that share corners with two equivalent O(3)Gd4 tetrahedra, corners with four equivalent O(1)Gd3Ga tetrahedra, corners with six equivalent O(4)Gd3Ga trigonal pyramids, edges with three equivalent O(3)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Ga trigonal pyramid. In the fourth O site, O(4) is bonded to one Gd(1), two equivalent Gd(2), and one Ga(1) atom to form distorted OGd3Ga trigonal pyramids that share corners with two equivalent O(1)Gd3Ga tetrahedra, corners with six equivalent O(3)Gd4 tetrahedra, corners with two equivalent O(4)Gd3Ga trigonal pyramids,  an edgeedge with one O(1)Gd3Ga tetrahedra,  an edgeedge with one O(3)Gd4 tetrahedra, and  an edgeedge with one O(4)Gd3Ga trigonal pyramid.