Materials Data on Na2UBr6 by Materials Project

Abstract

Na2UBr6 is beta Vanadium nitride-derived structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Na1+ is bonded to six Br1- atoms to form NaBr6 octahedra that share corners with four equivalent UBr6 octahedra, an edgeedge with one UBr6 octahedra, and edges with three equivalent NaBr6 octahedra. The corner-sharing octahedra tilt angles range from 46–47°. There are a spread of Na–Br bond distances ranging from 2.98–3.10 Å. There are two inequivalent U4+ sites. In the first U4+ site, U4+ is bonded to six Br1- atoms to form UBr6 octahedra that share corners with twelve equivalent NaBr6 octahedra. The corner-sharing octahedra tilt angles range from 46–47°. There are three shorter (2.79 Å) and three longer (2.81 Å) U–Br bond lengths. In the second U4+ site, U4+ is bonded to six equivalent Br1- atoms to form UBr6 octahedra that share edges with six equivalent NaBr6 octahedra. All U–Br bond lengths are 2.80 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted T-shaped geometry to two equivalent Na1+ and one U4+ atom. In the second Br1- site, Br1- is bonded in a distorted T-shaped geometry to two equivalent Na1+ and one U4+ atom. In the third Br1- site, Br1- is bonded in a distorted T-shaped geometry to two equivalent Na1+ and one U4+ atom.