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.

Na₂(CoO₂)₃结晶于正交晶系Amm2空间群，其结构为三维骨架结构。体系中存在三个不等价的Na⁺位点：在第一个Na⁺位点中，Na⁺以畸变五角锥配位几何与6个O²⁻阴离子成键，对应两组Na–O键长，其中2个键长为2.39 Å，剩余4个键长为2.46 Å；在第二个Na⁺位点中，Na⁺同样以畸变五角锥配位几何与6个O²⁻阴离子成键，对应两组Na–O键长，其中2个键长为2.47 Å，剩余4个键长为2.56 Å；在第三个Na⁺位点中，Na⁺以六配位几何与6个O²⁻阴离子成键，Na–O键距分布范围为2.39~2.54 Å。
体系中存在两个不等价的Co⁺3.33+位点：在第一个Co⁺3.33+位点中，该阳离子以矩形跷板式配位几何与4个O²⁻阴离子成键，Co–O键距分布范围为1.80~1.84 Å；在第二个Co⁺3.33+位点中，该阳离子同样以矩形跷板式配位几何与4个O²⁻阴离子成键，所有Co–O键长均为1.84 Å。
体系中存在四个不等价的O²⁻位点：在第一个O²⁻位点中，O²⁻以四配位几何与2个Na⁺和2个Co⁺3.33+阳离子成键；在第二个O²⁻位点中，O²⁻以四配位几何与2个Na⁺和2个Co⁺3.33+阳离子成键；在第三个O²⁻位点中，O²⁻以畸变三角平面配位几何与1个Na⁺和2个等价的Co⁺3.33+阳离子成键；在第四个O²⁻位点中，O²⁻以五配位几何与3个Na⁺和2个等价的Co⁺3.33+阳离子成键。