K3U2O6F7 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded to one O(1), one O(4), two equivalent F(2), and two equivalent F(3) atoms to form distorted KO2F4 octahedra that share corners with four equivalent U(1)O2F5 pentagonal bipyramids. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent F(3), and two equivalent F(4) atoms. In the third K site, K(3) is bonded in a distorted body-centered cubic geometry to two equivalent O(3), two equivalent O(4), two equivalent F(2), and two equivalent F(3) atoms. U(1) is bonded to one O(2), one O(3), one F(1), one F(2), one F(3), and two equivalent F(4) atoms to form UO2F5 pentagonal bipyramids that share corners with two equivalent K(1)O2F4 octahedra,  a cornercorner with one U(1)O2F5 pentagonal bipyramid, and  an edgeedge with one U(1)O2F5 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 58-61°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one K(1) and one K(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(2) and one U(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(3) and one U(1) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one K(1) and two equivalent K(3) atoms. There are four inequivalent F sites. In the first F site, F(4) is bonded in a trigonal planar geometry to one K(2) and two equivalent U(1) atoms. In the second F site, F(1) is bonded in a bent 150 degrees geometry to two equivalent U(1) atoms. In the third F site, F(2) is bonded in a trigonal planar geometry to one K(1), one K(3), and one U(1) atom. In the fourth F site, F(3) is bonded to one K(1), one K(2), one K(3), and one U(1) atom to form a mixture of distorted corner and edge-sharing FK3U tetrahedra.
K3U2O6F7 crystallizes in the monoclinic P2_1/m space group. There are three inequivalent K sites. In the first K site, K(1) is bonded to one O(1), one O(4), two equivalent F(2), and two equivalent F(3) atoms to form distorted KO2F4 octahedra that share corners with four equivalent U(1)O2F5 pentagonal bipyramids. The K(1)-O(1) bond length is 2.81 Å. The K(1)-O(4) bond length is 2.93 Å. Both K(1)-F(2) bond lengths are 2.58 Å. Both K(1)-F(3) bond lengths are 2.69 Å. In the second K site, K(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent F(3), and two equivalent F(4) atoms. The K(2)-O(1) bond length is 2.93 Å. Both K(2)-O(2) bond lengths are 2.79 Å. Both K(2)-F(3) bond lengths are 2.81 Å. Both K(2)-F(4) bond lengths are 2.68 Å. In the third K site, K(3) is bonded in a distorted body-centered cubic geometry to two equivalent O(3), two equivalent O(4), two equivalent F(2), and two equivalent F(3) atoms. Both K(3)-O(3) bond lengths are 2.94 Å. Both K(3)-O(4) bond lengths are 3.09 Å. Both K(3)-F(2) bond lengths are 2.65 Å. Both K(3)-F(3) bond lengths are 2.86 Å. U(1) is bonded to one O(2), one O(3), one F(1), one F(2), one F(3), and two equivalent F(4) atoms to form UO2F5 pentagonal bipyramids that share corners with two equivalent K(1)O2F4 octahedra,  a cornercorner with one U(1)O2F5 pentagonal bipyramid, and  an edgeedge with one U(1)O2F5 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 58-61°. The U(1)-O(2) bond length is 1.81 Å. The U(1)-O(3) bond length is 1.83 Å. The U(1)-F(1) bond length is 2.37 Å. The U(1)-F(2) bond length is 2.22 Å. The U(1)-F(3) bond length is 2.26 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) U(1)-F(4) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one K(1) and one K(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(2) and one U(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(3) and one U(1) atom. In the fourth O site, O(4) is bonded in a T-shaped geometry to one K(1) and two equivalent K(3) atoms. There are four inequivalent F sites. In the first F site, F(4) is bonded in a trigonal planar geometry to one K(2) and two equivalent U(1) atoms. In the second F site, F(1) is bonded in a bent 150 degrees geometry to two equivalent U(1) atoms. In the third F site, F(2) is bonded in a trigonal planar geometry to one K(1), one K(3), and one U(1) atom. In the fourth F site, F(3) is bonded to one K(1), one K(2), one K(3), and one U(1) atom to form a mixture of distorted corner and edge-sharing FK3U tetrahedra.