DOE OSTI2020
U3CuO10 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent CuO6 octahedra, corners with four equivalent UO7 pentagonal bipyramids, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. There are a spread of U–O bond distances ranging from 2.00–2.29 Å. In the second U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent UO6 octahedra, corners with two equivalent CuO6 octahedra, an edgeedge with one UO6 octahedra, an edgeedge with one CuO6 octahedra, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 4–40°. There are a spread of U–O bond distances ranging from 1.84–2.56 Å. Cu2+ is bonded to six O2- atoms to form CuO6 octahedra that share corners with two equivalent UO6 octahedra, corners with four equivalent UO7 pentagonal bipyramids, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 31°. There are a spread of Cu–O bond distances ranging from 1.95–2.37 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two U6+ and one Cu2+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to one U6+ and one Cu2+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent U6+ and one Cu2+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three U6+ atoms.