U3O10 crystallizes in the triclinic P-1 space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing UO6 octahedra. In the second U site, U(2) is bonded to one O(1), one O(4), one O(5), two equivalent O(2), and two equivalent O(3) atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent U(1)O6 octahedra,  an edgeedge with one U(1)O6 octahedra, and edges with two equivalent U(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 3-35°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one U(1) and one U(2) atom. In the second O site, O(2) is bonded in a water-like geometry to two equivalent U(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one U(1) and two equivalent U(2) atoms. In the fourth O site, O(4) is bonded in a linear geometry to one U(1) and one U(2) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to one U(2) atom.
U3O10 crystallizes in the triclinic P-1 space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing UO6 octahedra. Both U(1)-O(1) bond lengths are 1.88 Å. Both U(1)-O(3) bond lengths are 2.10 Å. Both U(1)-O(4) bond lengths are 2.35 Å. In the second U site, U(2) is bonded to one O(1), one O(4), one O(5), two equivalent O(2), and two equivalent O(3) atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent U(1)O6 octahedra,  an edgeedge with one U(1)O6 octahedra, and edges with two equivalent U(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 3-35°. The U(2)-O(1) bond length is 2.48 Å. The U(2)-O(4) bond length is 1.91 Å. The U(2)-O(5) bond length is 1.83 Å. There is one shorter (2.13 Å) and one longer (2.14 Å) U(2)-O(2) bond length. There is one shorter (2.32 Å) and one longer (2.51 Å) U(2)-O(3) bond length. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one U(1) and one U(2) atom. In the second O site, O(2) is bonded in a water-like geometry to two equivalent U(2) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one U(1) and two equivalent U(2) atoms. In the fourth O site, O(4) is bonded in a linear geometry to one U(1) and one U(2) atom. In the fifth O site, O(5) is bonded in a single-bond geometry to one U(2) atom.