Materials Data on Na2OsO4 by Materials Project

Abstract

Na2OsO4 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six equivalent O2- atoms to form distorted NaO6 pentagonal pyramids that share corners with six equivalent OsO6 octahedra, edges with three equivalent OsO6 octahedra, and faces with two equivalent NaO6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 10°. All Na–O bond lengths are 2.47 Å. In the second Na1+ site, Na1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are six shorter (2.53 Å) and three longer (2.82 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.59 Å. Os6+ is bonded to six O2- atoms to form OsO6 octahedra that share corners with two equivalent NaO6 pentagonal pyramids, edges with two equivalent OsO6 octahedra, and an edgeedge with one NaO6 pentagonal pyramid. There are a spread of Os–O bond distances ranging from 1.81–2.07 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Na1+ and two equivalent Os6+ atoms to form a mixture of distorted edge, face, and corner-sharing ONa4Os2 octahedra. The corner-sharing octahedral tilt angles are 45°. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Na1+ and two equivalent Os6+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and one Os6+ atom.