Materials Data on Na3(CoO2)4 by Materials Project

Na3(CoO2)4 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with six equivalent CoO6 octahedra, edges with four NaO6 octahedra, and edges with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 11–17°. There are a spread of Na–O bond distances ranging from 2.38–2.42 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with six equivalent CoO6 octahedra, edges with four equivalent NaO6 octahedra, and edges with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 11–15°. There are two shorter (2.36 Å) and four longer (2.41 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 CoO6 octahedra that share corners with six equivalent NaO6 octahedra, edges with four NaO6 octahedra, and edges with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 11–17°. There are a spread of Co–O bond distances ranging from 1.99–2.08 Å. In the second Co+3.25+ site, Co+3.25+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six equivalent NaO6 octahedra, edges with four equivalent NaO6 octahedra, and edges with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 11–15°. There are two shorter (2.03 Å) and four longer (2.04 Å) Co–O bond lengths. In the third Co+3.25+ site, Co+3.25+ is bonded to six O2- atoms to form CoO6 octahedra that share edges with six NaO6 octahedra and edges with six CoO6 octahedra. There is two shorter (1.87 Å) and four longer (2.00 Å) Co–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+ and three Co+3.25+ atoms to form ONa3Co3 octahedra that share corners with six equivalent ONa3Co3 octahedra and edges with twelve ONa2Co3 square pyramids. The corner-sharing octahedral tilt angles are 0°. 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 two equivalent Na1+ and three Co+3.25+ atoms to form distorted ONa2Co3 square pyramids that share corners with nine ONa2Co3 square pyramids, edges with four equivalent ONa3Co3 octahedra, and edges with four equivalent ONa2Co3 square pyramids.