Materials Data on Na2UO4 by Materials Project

Abstract

Na2UO4 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent NaO6 octahedra, edges with four equivalent NaO6 octahedra, and edges with four equivalent UO6 octahedra. The corner-sharing octahedra tilt angles range from 18–25°. There are four shorter (2.49 Å) and two longer (2.53 Å) Na–O bond lengths. U6+ is bonded to six O2- atoms to form UO6 octahedra that share edges with two equivalent UO6 octahedra and edges with eight equivalent NaO6 octahedra. There are two shorter (1.95 Å) and four longer (2.18 Å) U–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Na1+ and two equivalent U6+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to four equivalent Na1+ and one U6+ atom.