YGaO3 crystallizes in the hexagonal P6_3cm space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to one O(1), three equivalent O(3), and three equivalent O(4) atoms. In the second Y site, Y(2) is bonded to one O(2), three equivalent O(3), and three equivalent O(4) atoms to form distorted YO7 pentagonal bipyramids that share corners with three equivalent Ga(1)O5 trigonal bipyramids and edges with three equivalent Ga(1)O5 trigonal bipyramids. Ga(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form GaO5 trigonal bipyramids that share  a cornercorner with one Y(2)O7 pentagonal bipyramid, corners with six equivalent Ga(1)O5 trigonal bipyramids, and  an edgeedge with one Y(2)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Y(1) and three equivalent Ga(1) atoms to form OYGa3 trigonal pyramids that share corners with six equivalent O(3)Y3Ga tetrahedra, corners with three equivalent O(1)YGa3 trigonal pyramids, corners with three equivalent O(2)YGa3 trigonal pyramids, and edges with three equivalent O(4)Y3Ga tetrahedra. In the second O site, O(2) is bonded to one Y(2) and three equivalent Ga(1) atoms to form OYGa3 trigonal pyramids that share corners with six equivalent O(4)Y3Ga tetrahedra, corners with six equivalent O(1)YGa3 trigonal pyramids, and edges with three equivalent O(3)Y3Ga tetrahedra. In the third O site, O(3) is bonded to one Y(2), two equivalent Y(1), and one Ga(1) atom to form distorted OY3Ga tetrahedra that share corners with four equivalent O(4)Y3Ga tetrahedra, corners with six equivalent O(3)Y3Ga tetrahedra, corners with four equivalent O(1)YGa3 trigonal pyramids, edges with three equivalent O(4)Y3Ga tetrahedra, and  an edgeedge with one O(2)YGa3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Y(2), two equivalent Y(1), and one Ga(1) atom to form OY3Ga tetrahedra that share corners with four equivalent O(3)Y3Ga tetrahedra, corners with six equivalent O(4)Y3Ga tetrahedra, corners with two equivalent O(2)YGa3 trigonal pyramids, edges with three equivalent O(3)Y3Ga tetrahedra, and edges with two equivalent O(1)YGa3 trigonal pyramids.
YGaO3 crystallizes in the hexagonal P6_3cm space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a 7-coordinate geometry to one O(1), three equivalent O(3), and three equivalent O(4) atoms. The Y(1)-O(1) bond length is 2.51 Å. All Y(1)-O(3) bond lengths are 2.33 Å. All Y(1)-O(4) bond lengths are 2.28 Å. In the second Y site, Y(2) is bonded to one O(2), three equivalent O(3), and three equivalent O(4) atoms to form distorted YO7 pentagonal bipyramids that share corners with three equivalent Ga(1)O5 trigonal bipyramids and edges with three equivalent Ga(1)O5 trigonal bipyramids. The Y(2)-O(2) bond length is 2.39 Å. All Y(2)-O(3) bond lengths are 2.33 Å. All Y(2)-O(4) bond lengths are 2.30 Å. Ga(1) is bonded to one O(2), one O(3), one O(4), and two equivalent O(1) atoms to form GaO5 trigonal bipyramids that share  a cornercorner with one Y(2)O7 pentagonal bipyramid, corners with six equivalent Ga(1)O5 trigonal bipyramids, and  an edgeedge with one Y(2)O7 pentagonal bipyramid. The Ga(1)-O(2) bond length is 2.07 Å. The Ga(1)-O(3) bond length is 1.90 Å. The Ga(1)-O(4) bond length is 1.91 Å. Both Ga(1)-O(1) bond lengths are 2.05 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Y(1) and three equivalent Ga(1) atoms to form OYGa3 trigonal pyramids that share corners with six equivalent O(3)Y3Ga tetrahedra, corners with three equivalent O(1)YGa3 trigonal pyramids, corners with three equivalent O(2)YGa3 trigonal pyramids, and edges with three equivalent O(4)Y3Ga tetrahedra. In the second O site, O(2) is bonded to one Y(2) and three equivalent Ga(1) atoms to form OYGa3 trigonal pyramids that share corners with six equivalent O(4)Y3Ga tetrahedra, corners with six equivalent O(1)YGa3 trigonal pyramids, and edges with three equivalent O(3)Y3Ga tetrahedra. In the third O site, O(3) is bonded to one Y(2), two equivalent Y(1), and one Ga(1) atom to form distorted OY3Ga tetrahedra that share corners with four equivalent O(4)Y3Ga tetrahedra, corners with six equivalent O(3)Y3Ga tetrahedra, corners with four equivalent O(1)YGa3 trigonal pyramids, edges with three equivalent O(4)Y3Ga tetrahedra, and  an edgeedge with one O(2)YGa3 trigonal pyramid. In the fourth O site, O(4) is bonded to one Y(2), two equivalent Y(1), and one Ga(1) atom to form OY3Ga tetrahedra that share corners with four equivalent O(3)Y3Ga tetrahedra, corners with six equivalent O(4)Y3Ga tetrahedra, corners with two equivalent O(2)YGa3 trigonal pyramids, edges with three equivalent O(3)Y3Ga tetrahedra, and edges with two equivalent O(1)YGa3 trigonal pyramids.