DOE OSTI2020
Li2UO4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with two equivalent LiO6 octahedra, corners with four equivalent UO6 octahedra, an edgeedge with one UO6 octahedra, and edges with two equivalent LiO6 octahedra. The corner-sharing octahedra tilt angles range from 52–69°. There are a spread of Li–O bond distances ranging from 1.92–2.01 Å. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with four equivalent UO6 octahedra, corners with two equivalent LiO4 tetrahedra, edges with two equivalent LiO6 octahedra, edges with two equivalent UO6 octahedra, and edges with two equivalent LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–53°. There are a spread of Li–O bond distances ranging from 2.08–2.32 Å. U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four equivalent LiO6 octahedra, corners with four equivalent UO6 octahedra, corners with four equivalent LiO4 tetrahedra, edges with two equivalent LiO6 octahedra, and an edgeedge with one LiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–53°. There are a spread of U–O bond distances ranging from 1.94–2.20 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three Li1+ and one U6+ atom to form corner-sharing OLi3U tetrahedra. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Li1+ and one U6+ atom. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Li1+ and two equivalent U6+ atoms.