U3W2O17F2 crystallizes in the monoclinic C2/m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to one O(2), one O(3), one O(5), one O(7), two equivalent O(1), and one F(2) atom to form distorted UO6F pentagonal bipyramids that share corners with three equivalent W(1)O6 octahedra,  a cornercorner with one U(1)O6F pentagonal bipyramid,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one U(1)O6F pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 31-40°. In the second U site, U(2) is bonded to one O(10), one O(8), one O(9), two equivalent O(6), and two equivalent F(1) atoms to form distorted UO5F2 pentagonal bipyramids that share corners with two equivalent W(1)O6 octahedra and  an edgeedge with one U(2)O5F2 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 20°. W(1) is bonded to one O(1), one O(2), one O(4), one O(6), and two equivalent O(3) atoms to form distorted WO6 octahedra that share  a cornercorner with one U(2)O5F2 pentagonal bipyramid, corners with three equivalent U(1)O6F pentagonal bipyramids,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one U(1)O6F pentagonal bipyramid. There are ten inequivalent O sites. In the first O site, O(4) is bonded in a single-bond geometry to one W(1) atom. In the second O site, O(5) is bonded in a single-bond geometry to one U(1) atom. In the third O site, O(6) is bonded in a bent 150 degrees geometry to one U(2) and one W(1) atom. In the fourth O site, O(7) is bonded in a single-bond geometry to one U(1) atom. In the fifth O site, O(8) is bonded in a single-bond geometry to one U(2) atom. In the sixth O site, O(9) is bonded in a single-bond geometry to one U(2) atom. In the seventh O site, O(1) is bonded in a 3-coordinate geometry to two equivalent U(1) and one W(1) atom. In the eighth O site, O(10) is bonded in a single-bond geometry to one U(2) atom. In the ninth O site, O(2) is bonded in a bent 150 degrees geometry to one U(1) and one W(1) atom. In the tenth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one U(1) and two equivalent W(1) atoms. There are two inequivalent F sites. In the first F site, F(2) is bonded in a linear geometry to two equivalent U(1) atoms. In the second F site, F(1) is bonded in a bent 120 degrees geometry to two equivalent U(2) atoms.
U3W2O17F2 crystallizes in the monoclinic C2/m space group. There are two inequivalent U sites. In the first U site, U(1) is bonded to one O(2), one O(3), one O(5), one O(7), two equivalent O(1), and one F(2) atom to form distorted UO6F pentagonal bipyramids that share corners with three equivalent W(1)O6 octahedra,  a cornercorner with one U(1)O6F pentagonal bipyramid,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one U(1)O6F pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 31-40°. The U(1)-O(2) bond length is 2.38 Å. The U(1)-O(3) bond length is 2.41 Å. The U(1)-O(5) bond length is 1.79 Å. The U(1)-O(7) bond length is 1.79 Å. Both U(1)-O(1) bond lengths are 2.47 Å. The U(1)-F(2) bond length is 2.27 Å. In the second U site, U(2) is bonded to one O(10), one O(8), one O(9), two equivalent O(6), and two equivalent F(1) atoms to form distorted UO5F2 pentagonal bipyramids that share corners with two equivalent W(1)O6 octahedra and  an edgeedge with one U(2)O5F2 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 20°. The U(2)-O(10) bond length is 1.80 Å. The U(2)-O(8) bond length is 1.80 Å. The U(2)-O(9) bond length is 2.43 Å. Both U(2)-O(6) bond lengths are 2.36 Å. Both U(2)-F(1) bond lengths are 2.33 Å. W(1) is bonded to one O(1), one O(2), one O(4), one O(6), and two equivalent O(3) atoms to form distorted WO6 octahedra that share  a cornercorner with one U(2)O5F2 pentagonal bipyramid, corners with three equivalent U(1)O6F pentagonal bipyramids,  an edgeedge with one W(1)O6 octahedra, and  an edgeedge with one U(1)O6F pentagonal bipyramid. The W(1)-O(1) bond length is 1.91 Å. The W(1)-O(2) bond length is 1.84 Å. The W(1)-O(4) bond length is 2.10 Å. The W(1)-O(6) bond length is 1.81 Å. There is one shorter (2.00 Å) and one longer (2.12 Å) W(1)-O(3) bond length. There are ten inequivalent O sites. In the first O site, O(4) is bonded in a single-bond geometry to one W(1) atom. In the second O site, O(5) is bonded in a single-bond geometry to one U(1) atom. In the third O site, O(6) is bonded in a bent 150 degrees geometry to one U(2) and one W(1) atom. In the fourth O site, O(7) is bonded in a single-bond geometry to one U(1) atom. In the fifth O site, O(8) is bonded in a single-bond geometry to one U(2) atom. In the sixth O site, O(9) is bonded in a single-bond geometry to one U(2) atom. In the seventh O site, O(1) is bonded in a 3-coordinate geometry to two equivalent U(1) and one W(1) atom. In the eighth O site, O(10) is bonded in a single-bond geometry to one U(2) atom. In the ninth O site, O(2) is bonded in a bent 150 degrees geometry to one U(1) and one W(1) atom. In the tenth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one U(1) and two equivalent W(1) atoms. There are two inequivalent F sites. In the first F site, F(2) is bonded in a linear geometry to two equivalent U(1) atoms. In the second F site, F(1) is bonded in a bent 120 degrees geometry to two equivalent U(2) atoms.