Materials Data on Na4Er2(IrO4)3 by Materials Project

Abstract

Na4Er2(IrO4)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first 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 2.27–2.50 Å. In the second Na1+ site, Na1+ is bonded to six equivalent O2- atoms to form distorted NaO6 pentagonal pyramids that share corners with six equivalent IrO6 octahedra, edges with three equivalent IrO6 octahedra, and faces with two equivalent NaO6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 11°. All Na–O bond lengths are 2.46 Å. Er3+ is bonded in a 6-coordinate geometry to nine O2- atoms. There are six shorter (2.31 Å) and three longer (2.76 Å) Er–O bond lengths. Ir+4.67+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with two equivalent NaO6 pentagonal pyramids, edges with two equivalent IrO6 octahedra, and an edgeedge with one NaO6 pentagonal pyramid. There are four shorter (2.00 Å) and two longer (2.04 Å) Ir–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Na1+ and two equivalent Ir+4.67+ atoms to form distorted ONa4Ir2 octahedra that share corners with four equivalent ONa4Ir2 octahedra, corners with four equivalent ONa2Er2Ir trigonal bipyramids, edges with two equivalent ONa4Ir2 octahedra, edges with four equivalent ONa2Er2Ir trigonal bipyramids, and faces with two equivalent ONa4Ir2 octahedra. The corner-sharing octahedral tilt angles are 45°. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, two equivalent Er3+, and two equivalent Ir+4.67+ atoms. In the third O2- site, O2- is bonded to two equivalent Na1+, two equivalent Er3+, and one Ir+4.67+ atom to form distorted ONa2Er2Ir trigonal bipyramids that share corners with two equivalent ONa4Ir2 octahedra, corners with seven equivalent ONa2Er2Ir trigonal bipyramids, edges with two equivalent ONa4Ir2 octahedra, and edges with five equivalent ONa2Er2Ir trigonal bipyramids. The corner-sharing octahedral tilt angles are 51°.