Materials Data on NaU3O8 by Materials Project
NaU3O8 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Na1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are three shorter (2.42 Å) and six longer (2.68 Å) Na–O bond lengths. U5+ is bonded to six O2- atoms to form distorted corner-sharing UO6 octahedra. The corner-sharing octahedra tilt angles range from 5–60°. There are a spread of U–O bond distances ranging from 2.12–2.22 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a T-shaped geometry to one Na1+ and two equivalent U5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two equivalent U5+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three equivalent U5+ atoms.