Materials Data on Na2(CoO2)3 by Materials Project

Na2(CoO2)3 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted pentagonal pyramidal geometry to six O2- atoms. There are two shorter (2.39 Å) and four longer (2.46 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a distorted pentagonal pyramidal geometry to six O2- atoms. There are two shorter (2.47 Å) and four longer (2.56 Å) Na–O bond lengths. In the third 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 2.39–2.54 Å. There are two inequivalent Co+3.33+ sites. In the first Co+3.33+ site, Co+3.33+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Co–O bond distances ranging from 1.80–1.84 Å. In the second Co+3.33+ site, Co+3.33+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. All Co–O bond lengths are 1.84 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Co+3.33+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two Co+3.33+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two equivalent Co+3.33+ atoms. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+ and two equivalent Co+3.33+ atoms.