DOI: 10.17188/1296344
title: Materials Data on Na5(NiO2)8 by Materials Project

description: Na5(NiO2)8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.25–2.56 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.36–2.40 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with six NiO6 octahedra, edges with two equivalent NaO6 octahedra, and edges with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 12–17°. There are a spread of Na–O bond distances ranging from 2.35–2.38 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with six NiO6 octahedra, edges with two equivalent NaO6 octahedra, and edges with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Na–O bond distances ranging from 2.32–2.38 Å. There are four inequivalent Ni+3.38+ sites. In the first Ni+3.38+ site, Ni+3.38+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent NaO6 octahedra, an edgeedge with one NaO6 octahedra, and edges with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are a spread of Ni–O bond distances ranging from 1.88–2.12 Å. In the second Ni+3.38+ site, Ni+3.38+ is bonded to six O2- atoms to form NiO6 octahedra that share a cornercorner with one NaO6 octahedra, edges with two NaO6 octahedra, and edges with six NiO6 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Ni–O bond distances ranging from 1.87–1.92 Å. In the third Ni+3.38+ site, Ni+3.38+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two equivalent NaO6 octahedra, an edgeedge with one NaO6 octahedra, and edges with six NiO6 octahedra. The corner-sharing octahedra tilt angles range from 12–16°. There are a spread of Ni–O bond distances ranging from 1.88–2.04 Å. In the fourth Ni+3.38+ site, Ni+3.38+ is bonded to six O2- atoms to form NiO6 octahedra that share a cornercorner with one NaO6 octahedra, edges with two NaO6 octahedra, and edges with six NiO6 octahedra. The corner-sharing octahedral tilt angles are 14°. There are a spread of Ni–O bond distances ranging from 1.88–2.10 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+ and three Ni+3.38+ atoms to form distorted ONa3Ni3 octahedra that share corners with two equivalent ONa3Ni3 octahedra, corners with four ONa2Ni3 square pyramids, edges with nine ONa2Ni3 square pyramids, and edges with three ONaNi3 trigonal pyramids. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded to two Na1+ and three Ni+3.38+ atoms to form distorted ONa2Ni3 square pyramids that share a cornercorner with one ONa3Ni3 octahedra, corners with four ONa2Ni3 square pyramids, corners with four ONaNi3 trigonal pyramids, an edgeedge with one ONa3Ni3 octahedra, edges with six ONa2Ni3 square pyramids, and an edgeedge with one ONaNi3 trigonal pyramid. The corner-sharing octahedral tilt angles are 12°. In the third O2- site, O2- is bonded to two Na1+ and three Ni+3.38+ atoms to form ONa2Ni3 square pyramids that share corners with two equivalent ONa3Ni3 octahedra, corners with five ONa2Ni3 square pyramids, corners with two ONaNi3 trigonal pyramids, an edgeedge with one ONa3Ni3 octahedra, edges with four ONa2Ni3 square pyramids, and edges with three ONaNi3 trigonal pyramids. The corner-sharing octahedra tilt angles range from 1–2°. In the fourth O2- site, O2- is bonded to two Na1+ and three Ni+3.38+ atoms to form ONa2Ni3 square pyramids that share corners with six ONa2Ni3 square pyramids, corners with three equivalent ONaNi3 trigonal pyramids, edges with three equivalent ONa3Ni3 octahedra, edges with four ONa2Ni3 square pyramids, and an edgeedge with one ONaNi3 trigonal pyramid. In the fifth O2- site, O2- is bonded to one Na1+ and three Ni+3.38+ atoms to form distorted ONaNi3 trigonal pyramids that share corners with seven ONa2Ni3 square pyramids, corners with three ONaNi3 trigonal pyramids, an edgeedge with one ONa3Ni3 octahedra, and edges with four ONa2Ni3 square pyramids. In the sixth O2- site, O2- is bonded to two Na1+ and three Ni+3.38+ atoms to form distorted ONa2Ni3 square pyramids that share corners with five ONa2Ni3 square pyramids, corners with four ONaNi3 trigonal pyramids, edges with two equivalent ONa3Ni3 octahedra, and edges with six ONa2Ni3 square pyramids. In the seventh O2- site, O2- is bonded to one Na1+ and three Ni+3.38+ atoms to form distorted ONaNi3 trigonal pyramids that share corners with eight ONa2Ni3 square pyramids, corners with two equivalent ONaNi3 trigonal pyramids, edges with two equivalent ONa3Ni3 octahedra, edges with two equivalent ONa2Ni3 square pyramids, and an edgeedge with one ONaNi3 trigonal pyramid. In the eighth O2- site, O2- is bonded to two Na1+ and three Ni+3.38+ atoms to form distorted ONa2Ni3 square pyramids that share a cornercorner with one ONa3Ni3 octahedra, corners with six ONa2Ni3 square pyramids, corners with two ONaNi3 trigonal pyramids, edges with two equivalent ONa3Ni3 octahedra, edges with five ONa2Ni3 square pyramids, and an edgeedge with one ONaNi3 trigonal pyramid. The corner-sharing octahedral tilt angles are 1°.