Materials Data on Na3U6CrF30 by Materials Project

Abstract

Na3U6CrF30 crystallizes in the trigonal P-3c1 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted pentagonal pyramidal geometry to six F1- atoms. There are three shorter (2.28 Å) and three longer (2.35 Å) Na–F bond lengths. In the second Na1+ site, Na1+ is bonded to twelve F1- atoms to form NaF12 cuboctahedra that share faces with two equivalent CrF6 octahedra. There are six shorter (2.63 Å) and six longer (2.67 Å) Na–F bond lengths. U4+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of U–F bond distances ranging from 2.26–2.43 Å. Cr3+ is bonded to six equivalent F1- atoms to form CrF6 octahedra that share faces with two equivalent NaF12 cuboctahedra. All Cr–F bond lengths are 1.95 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+ and two equivalent U4+ atoms. In the second F1- site, F1- is bonded in a bent 150 degrees geometry to two equivalent U4+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to one Na1+ and two equivalent U4+ atoms. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to one Na1+ and two equivalent U4+ atoms. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to one Na1+, one U4+, and one Cr3+ atom.