K4U(PO5)2 crystallizes in the tetragonal P4_2/nmc space group. K(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), and four equivalent O(1) atoms. U(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form UO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra. P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with two equivalent U(1)O6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to four equivalent K(1) and one P(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one U(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1) and one U(1) atom.
K4U(PO5)2 crystallizes in the tetragonal P4_2/nmc space group. K(1) is bonded in a 7-coordinate geometry to one O(3), two equivalent O(2), and four equivalent O(1) atoms. The K(1)-O(3) bond length is 2.75 Å. Both K(1)-O(2) bond lengths are 2.95 Å. There are two shorter (2.82 Å) and two longer (3.02 Å) K(1)-O(1) bond lengths. U(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form UO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra. Both U(1)-O(3) bond lengths are 1.85 Å. All U(1)-O(2) bond lengths are 2.26 Å. P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with two equivalent U(1)O6 octahedra. The corner-sharing octahedral tilt angles are 40°. Both P(1)-O(1) bond lengths are 1.53 Å. Both P(1)-O(2) bond lengths are 1.59 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to four equivalent K(1) and one P(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one U(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent K(1) and one U(1) atom.