Materials Data on Na3(CoO2)4 by Materials Project

Abstract

Na3(CoO2)4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two 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 2.29–2.52 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are four shorter (2.37 Å) and two longer (2.40 Å) Na–O bond lengths. There are three inequivalent Co+3.25+ sites. In the first Co+3.25+ site, Co+3.25+ is bonded to six O2- atoms to form edge-sharing CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.90–2.03 Å. In the second Co+3.25+ site, Co+3.25+ is bonded to six O2- atoms to form edge-sharing CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.96–2.01 Å. In the third Co+3.25+ site, Co+3.25+ is bonded to six O2- atoms to form edge-sharing CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.95–2.04 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Na1+ and three Co+3.25+ atoms to form ONa2Co3 square pyramids that share corners with three equivalent ONa3Co3 octahedra, corners with six ONa2Co3 square pyramids, edges with three equivalent ONa3Co3 octahedra, and edges with five ONa2Co3 square pyramids. The corner-sharing octahedra tilt angles range from 1–2°. In the second O2- site, O2- is bonded to two Na1+ and three Co+3.25+ atoms to form ONa2Co3 square pyramids that share corners with nine ONa2Co3 square pyramids, edges with four equivalent ONa3Co3 octahedra, and edges with four ONa2Co3 square pyramids. In the third O2- site, O2- is bonded to three Na1+ and three Co+3.25+ atoms to form distorted ONa3Co3 octahedra that share corners with three equivalent ONa3Co3 octahedra, corners with three equivalent ONa2Co3 square pyramids, an edgeedge with one ONa3Co3 octahedra, and edges with eleven ONa2Co3 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to two Na1+ and three Co+3.25+ atoms to form ONa2Co3 square pyramids that share corners with nine ONa2Co3 square pyramids, edges with four equivalent ONa3Co3 octahedra, and edges with four ONa2Co3 square pyramids.