K2U3H4(O3F4)2 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one H(1), one H(2), two equivalent O(2), two equivalent F(1), and two equivalent F(2) atoms. In the second K site, K(2) is bonded to one H(1), one H(2), one H(4), two equivalent F(2), and two equivalent F(4) atoms to form distorted KH3F4 pentagonal bipyramids that share corners with four equivalent U(1)O2F5 pentagonal bipyramids. There are two inequivalent U sites. In the first U site, U(1) is bonded to one O(1), one O(2), one F(1), one F(2), one F(4), and two equivalent F(3) atoms to form distorted UO2F5 pentagonal bipyramids that share corners with two equivalent K(2)H3F4 pentagonal bipyramids and corners with two equivalent U(1)O2F5 pentagonal bipyramids. In the second U site, U(2) is bonded in a 6-coordinate geometry to one H(3), two equivalent O(3), two equivalent F(1), and two equivalent F(4) atoms. There are four inequivalent H sites. In the first H site, H(1) is bonded in a distorted bent 120 degrees geometry to one K(1) and one K(2) atom. In the second H site, H(2) is bonded in an L-shaped geometry to one K(1) and one K(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one U(2) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one K(2) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one U(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one K(1) and one U(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to one U(2) atom. There are four inequivalent F sites. In the first F site, F(2) is bonded in a distorted trigonal planar geometry to one K(1), one K(2), and one U(1) atom. In the second F site, F(3) is bonded in a bent 150 degrees geometry to two equivalent U(1) atoms. In the third F site, F(4) is bonded in a trigonal planar geometry to one K(2), one U(1), and one U(2) atom. In the fourth F site, F(1) is bonded in a distorted bent 150 degrees geometry to one K(1), one U(1), and one U(2) atom.
K2U3H4(O3F4)2 crystallizes in the orthorhombic Ama2 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one H(1), one H(2), two equivalent O(2), two equivalent F(1), and two equivalent F(2) atoms. The K(1)-H(1) bond length is 2.87 Å. The K(1)-H(2) bond length is 2.89 Å. Both K(1)-O(2) bond lengths are 2.99 Å. Both K(1)-F(1) bond lengths are 3.13 Å. Both K(1)-F(2) bond lengths are 2.74 Å. In the second K site, K(2) is bonded to one H(1), one H(2), one H(4), two equivalent F(2), and two equivalent F(4) atoms to form distorted KH3F4 pentagonal bipyramids that share corners with four equivalent U(1)O2F5 pentagonal bipyramids. The K(2)-H(1) bond length is 2.82 Å. The K(2)-H(2) bond length is 2.89 Å. The K(2)-H(4) bond length is 2.85 Å. Both K(2)-F(2) bond lengths are 2.71 Å. Both K(2)-F(4) bond lengths are 2.88 Å. There are two inequivalent U sites. In the first U site, U(1) is bonded to one O(1), one O(2), one F(1), one F(2), one F(4), and two equivalent F(3) atoms to form distorted UO2F5 pentagonal bipyramids that share corners with two equivalent K(2)H3F4 pentagonal bipyramids and corners with two equivalent U(1)O2F5 pentagonal bipyramids. The U(1)-O(1) bond length is 1.79 Å. The U(1)-O(2) bond length is 1.82 Å. The U(1)-F(1) bond length is 2.38 Å. The U(1)-F(2) bond length is 2.23 Å. The U(1)-F(4) bond length is 2.48 Å. There is one shorter (2.33 Å) and one longer (2.37 Å) U(1)-F(3) bond length. In the second U site, U(2) is bonded in a 6-coordinate geometry to one H(3), two equivalent O(3), two equivalent F(1), and two equivalent F(4) atoms. The U(2)-H(3) bond length is 2.62 Å. Both U(2)-O(3) bond lengths are 1.81 Å. Both U(2)-F(1) bond lengths are 2.27 Å. Both U(2)-F(4) bond lengths are 2.30 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a distorted bent 120 degrees geometry to one K(1) and one K(2) atom. In the second H site, H(2) is bonded in an L-shaped geometry to one K(1) and one K(2) atom. In the third H site, H(3) is bonded in a single-bond geometry to one U(2) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one K(2) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one U(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one K(1) and one U(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to one U(2) atom. There are four inequivalent F sites. In the first F site, F(2) is bonded in a distorted trigonal planar geometry to one K(1), one K(2), and one U(1) atom. In the second F site, F(3) is bonded in a bent 150 degrees geometry to two equivalent U(1) atoms. In the third F site, F(4) is bonded in a trigonal planar geometry to one K(2), one U(1), and one U(2) atom. In the fourth F site, F(1) is bonded in a distorted bent 150 degrees geometry to one K(1), one U(1), and one U(2) atom.