DOE OSTI2020
(UPO6)2CuO4(O2)2 crystallizes in the tetragonal P4mm space group. The structure is two-dimensional and consists of one 1,2,3,4-tetraoxacyclobutane molecule; one CuO4 cluster; and one UPO6 sheet oriented in the (0, 0, 1) direction. In the CuO4 cluster, Cu is bonded in a rectangular see-saw-like geometry to four equivalent O atoms. All Cu–O bond lengths are 1.77 Å. O is bonded in a single-bond geometry to one Cu atom. In the UPO6 sheet, there are two inequivalent U sites. In the first U site, U is bonded to six O atoms to form UO6 octahedra that share corners with four equivalent PO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.82–2.25 Å. In the second U site, U is bonded to six O atoms to form UO6 octahedra that share corners with four equivalent PO4 tetrahedra. There are two shorter (1.81 Å) and four longer (2.25 Å) U–O bond lengths. P is bonded to four O atoms to form PO4 tetrahedra that share corners with four UO6 octahedra. The corner-sharing octahedra tilt angles range from 33–34°. There is two shorter (1.54 Å) and two longer (1.55 Å) P–O bond length. There are six inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one U atom. In the second O site, O is bonded in a single-bond geometry to one U atom. In the third O site, O is bonded in a bent 150 degrees geometry to one U and one P atom. In the fourth O site, O is bonded in a bent 150 degrees geometry to one U and one P atom. In the fifth O site, O is bonded in a single-bond geometry to one U atom. In the sixth O site, O is bonded in a single-bond geometry to one U atom.