Materials Data on Na2(CoO2)3 by Materials Project

(Na2Co3O5)2O2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional and consists of two hydrogen peroxide molecules and one Na2Co3O5 framework. In the Na2Co3O5 framework, there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Na–O bond lengths are 2.29 Å. In the second Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Na–O bond lengths are 2.52 Å. 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 2.39–2.83 Å. There are two inequivalent Co+3.33+ sites. In the first Co+3.33+ site, Co+3.33+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of Co–O bond distances ranging from 1.79–1.82 Å. In the second Co+3.33+ site, Co+3.33+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.85 Å) and two longer (1.86 Å) Co–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+ and two Co+3.33+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Na1+ and two Co+3.33+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Na1+ and two equivalent Co+3.33+ atoms.