U3Y2O11 is alpha bismuth trifluoride-derived structured and crystallizes in the orthorhombic Immm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. In the second U site, U(2) is bonded in a body-centered cubic geometry to two equivalent O(4), four equivalent O(2), and four equivalent O(3) atoms. Y(1) is bonded in a body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one U(1) and three equivalent Y(1) atoms to form OY3U tetrahedra that share corners with two equivalent O(4)U6 octahedra, corners with two equivalent O(3)U4 tetrahedra, corners with six equivalent O(2)YU3 tetrahedra, corners with eight equivalent O(1)Y3U tetrahedra, edges with two equivalent O(2)YU3 tetrahedra, and edges with four equivalent O(1)Y3U tetrahedra. The corner-sharing octahedral tilt angles are 56°. In the second O site, O(2) is bonded to one U(2), two equivalent U(1), and one Y(1) atom to form OYU3 tetrahedra that share corners with three equivalent O(4)U6 octahedra, corners with four equivalent O(3)U4 tetrahedra, corners with six equivalent O(1)Y3U tetrahedra, corners with six equivalent O(2)YU3 tetrahedra, edges with two equivalent O(3)U4 tetrahedra, edges with two equivalent O(1)Y3U tetrahedra, edges with two equivalent O(2)YU3 tetrahedra, and  a faceface with one O(4)U6 octahedra. The corner-sharing octahedral tilt angles range from 54-56°. In the third O site, O(3) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with two equivalent O(4)U6 octahedra, corners with four equivalent O(3)U4 tetrahedra, corners with four equivalent O(1)Y3U tetrahedra, corners with eight equivalent O(2)YU3 tetrahedra, edges with two equivalent O(3)U4 tetrahedra, edges with four equivalent O(2)YU3 tetrahedra, and faces with two equivalent O(4)U6 octahedra. The corner-sharing octahedral tilt angles are 58°. In the fourth O site, O(4) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form OU6 octahedra that share corners with two equivalent O(4)U6 octahedra, corners with four equivalent O(3)U4 tetrahedra, corners with eight equivalent O(1)Y3U tetrahedra, corners with twelve equivalent O(2)YU3 tetrahedra, edges with two equivalent O(4)U6 octahedra, faces with four equivalent O(3)U4 tetrahedra, and faces with four equivalent O(2)YU3 tetrahedra. The corner-sharing octahedra are not tilted.
U3Y2O11 is alpha bismuth trifluoride-derived structured and crystallizes in the orthorhombic Immm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and four equivalent O(2) atoms. Both U(1)-O(1) bond lengths are 2.19 Å. Both U(1)-O(3) bond lengths are 2.40 Å. Both U(1)-O(4) bond lengths are 2.64 Å. All U(1)-O(2) bond lengths are 2.37 Å. In the second U site, U(2) is bonded in a body-centered cubic geometry to two equivalent O(4), four equivalent O(2), and four equivalent O(3) atoms. Both U(2)-O(4) bond lengths are 2.72 Å. All U(2)-O(2) bond lengths are 2.29 Å. All U(2)-O(3) bond lengths are 2.24 Å. Y(1) is bonded in a body-centered cubic geometry to two equivalent O(2) and six equivalent O(1) atoms. Both Y(1)-O(2) bond lengths are 2.32 Å. There are two shorter (2.35 Å) and four longer (2.38 Å) Y(1)-O(1) bond lengths. There are four inequivalent O sites. In the first O site, O(1) is bonded to one U(1) and three equivalent Y(1) atoms to form OY3U tetrahedra that share corners with two equivalent O(4)U6 octahedra, corners with two equivalent O(3)U4 tetrahedra, corners with six equivalent O(2)YU3 tetrahedra, corners with eight equivalent O(1)Y3U tetrahedra, edges with two equivalent O(2)YU3 tetrahedra, and edges with four equivalent O(1)Y3U tetrahedra. The corner-sharing octahedral tilt angles are 56°. In the second O site, O(2) is bonded to one U(2), two equivalent U(1), and one Y(1) atom to form OYU3 tetrahedra that share corners with three equivalent O(4)U6 octahedra, corners with four equivalent O(3)U4 tetrahedra, corners with six equivalent O(1)Y3U tetrahedra, corners with six equivalent O(2)YU3 tetrahedra, edges with two equivalent O(3)U4 tetrahedra, edges with two equivalent O(1)Y3U tetrahedra, edges with two equivalent O(2)YU3 tetrahedra, and  a faceface with one O(4)U6 octahedra. The corner-sharing octahedral tilt angles range from 54-56°. In the third O site, O(3) is bonded to two equivalent U(1) and two equivalent U(2) atoms to form OU4 tetrahedra that share corners with two equivalent O(4)U6 octahedra, corners with four equivalent O(3)U4 tetrahedra, corners with four equivalent O(1)Y3U tetrahedra, corners with eight equivalent O(2)YU3 tetrahedra, edges with two equivalent O(3)U4 tetrahedra, edges with four equivalent O(2)YU3 tetrahedra, and faces with two equivalent O(4)U6 octahedra. The corner-sharing octahedral tilt angles are 58°. In the fourth O site, O(4) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form OU6 octahedra that share corners with two equivalent O(4)U6 octahedra, corners with four equivalent O(3)U4 tetrahedra, corners with eight equivalent O(1)Y3U tetrahedra, corners with twelve equivalent O(2)YU3 tetrahedra, edges with two equivalent O(4)U6 octahedra, faces with four equivalent O(3)U4 tetrahedra, and faces with four equivalent O(2)YU3 tetrahedra. The corner-sharing octahedra are not tilted.