Materials Data on CaCoO3 by Materials Project
CaCoO3 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of one CaCoO3 sheet oriented in the (0, 0, 1) direction. Ca2+ is bonded to five O2- atoms to form CaO5 square pyramids that share corners with four equivalent CaO5 square pyramids, edges with four equivalent CoO6 octahedra, and edges with four equivalent CaO5 square pyramids. There are one shorter (2.16 Å) and four longer (2.26 Å) Ca–O bond lengths. Co4+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with four equivalent CoO6 octahedra, edges with four equivalent CoO6 octahedra, and edges with four equivalent CaO5 square pyramids. The corner-sharing octahedra tilt angles range from 6–7°. There are a spread of Co–O bond distances ranging from 1.61–2.28 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ca2+ and one Co4+ atom to form a mixture of edge and corner-sharing OCa4Co square pyramids. In the second O2- site, O2- is bonded in a single-bond geometry to one Co4+ atom. In the third O2- site, O2- is bonded to one Ca2+ and four equivalent Co4+ atoms to form OCaCo4 square pyramids that share corners with four equivalent OCaCo4 square pyramids and edges with eight OCa4Co square pyramids.