U3O10 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent U sites. In the first U site, U(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted UO6 octahedra that share corners with four equivalent U(2)O6 octahedra, corners with two equivalent U(3)O7 pentagonal bipyramids, and  an edgeedge with one U(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 55-66°. In the second U site, U(2) is bonded to one O(2), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted UO6 octahedra that share corners with four equivalent U(1)O6 octahedra,  a cornercorner with one U(3)O7 pentagonal bipyramid, and edges with two equivalent U(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-66°. In the third U site, U(3) is bonded to one O(10), one O(8), one O(9), two equivalent O(1), and two equivalent O(5) atoms to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one U(2)O6 octahedra, corners with two equivalent U(1)O6 octahedra,  an edgeedge with one U(1)O6 octahedra, and edges with two equivalent U(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 11-45°. There are ten inequivalent O sites. In the first O site, O(6) is bonded in a trigonal non-coplanar geometry to one U(1) and two equivalent U(2) atoms. In the second O site, O(7) is bonded in a single-bond geometry to one U(1) atom. In the third O site, O(8) is bonded in a distorted linear geometry to one U(2) and one U(3) atom. In the fourth O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one U(1) and two equivalent U(3) atoms. In the fifth O site, O(9) is bonded in a single-bond geometry to one U(3) atom. In the sixth O site, O(2) is bonded in a single-bond geometry to one U(2) atom. In the seventh O site, O(10) is bonded in a single-bond geometry to one U(3) atom. In the eighth O site, O(3) is bonded in a trigonal planar geometry to one U(1) and two equivalent U(2) atoms. In the ninth O site, O(4) is bonded in a single-bond geometry to one U(1) atom. In the tenth O site, O(5) is bonded in a distorted trigonal planar geometry to one U(1) and two equivalent U(3) atoms.
U3O10 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent U sites. In the first U site, U(1) is bonded to one O(1), one O(3), one O(4), one O(5), one O(6), and one O(7) atom to form distorted UO6 octahedra that share corners with four equivalent U(2)O6 octahedra, corners with two equivalent U(3)O7 pentagonal bipyramids, and  an edgeedge with one U(3)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 55-66°. The U(1)-O(1) bond length is 2.20 Å. The U(1)-O(3) bond length is 2.29 Å. The U(1)-O(4) bond length is 1.83 Å. The U(1)-O(5) bond length is 2.21 Å. The U(1)-O(6) bond length is 2.34 Å. The U(1)-O(7) bond length is 1.82 Å. In the second U site, U(2) is bonded to one O(2), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form distorted UO6 octahedra that share corners with four equivalent U(1)O6 octahedra,  a cornercorner with one U(3)O7 pentagonal bipyramid, and edges with two equivalent U(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-66°. The U(2)-O(2) bond length is 1.82 Å. The U(2)-O(8) bond length is 1.88 Å. There is one shorter (2.24 Å) and one longer (2.30 Å) U(2)-O(3) bond length. There is one shorter (2.25 Å) and one longer (2.28 Å) U(2)-O(6) bond length. In the third U site, U(3) is bonded to one O(10), one O(8), one O(9), two equivalent O(1), and two equivalent O(5) atoms to form distorted UO7 pentagonal bipyramids that share  a cornercorner with one U(2)O6 octahedra, corners with two equivalent U(1)O6 octahedra,  an edgeedge with one U(1)O6 octahedra, and edges with two equivalent U(3)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 11-45°. The U(3)-O(10) bond length is 1.81 Å. The U(3)-O(8) bond length is 2.40 Å. The U(3)-O(9) bond length is 1.80 Å. There is one shorter (2.26 Å) and one longer (2.39 Å) U(3)-O(1) bond length. There is one shorter (2.27 Å) and one longer (2.38 Å) U(3)-O(5) bond length. There are ten inequivalent O sites. In the first O site, O(6) is bonded in a trigonal non-coplanar geometry to one U(1) and two equivalent U(2) atoms. In the second O site, O(7) is bonded in a single-bond geometry to one U(1) atom. In the third O site, O(8) is bonded in a distorted linear geometry to one U(2) and one U(3) atom. In the fourth O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to one U(1) and two equivalent U(3) atoms. In the fifth O site, O(9) is bonded in a single-bond geometry to one U(3) atom. In the sixth O site, O(2) is bonded in a single-bond geometry to one U(2) atom. In the seventh O site, O(10) is bonded in a single-bond geometry to one U(3) atom. In the eighth O site, O(3) is bonded in a trigonal planar geometry to one U(1) and two equivalent U(2) atoms. In the ninth O site, O(4) is bonded in a single-bond geometry to one U(1) atom. In the tenth O site, O(5) is bonded in a distorted trigonal planar geometry to one U(1) and two equivalent U(3) atoms.