Materials Data on K4Co2O5 by Materials Project
K4Co2O5 crystallizes in the orthorhombic Pmn2_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.69–2.79 Å. In the second K1+ site, K1+ is bonded to four O2- atoms to form distorted corner-sharing KO4 trigonal pyramids. All K–O bond lengths are 2.70 Å. There are two inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.74 Å) and one longer (1.78 Å) Co–O bond length. In the second Co3+ site, Co3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.73 Å) and one longer (1.81 Å) Co–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a square co-planar geometry to two equivalent K1+ and two Co3+ atoms. In the second O2- site, O2- is bonded to four K1+ and one Co3+ atom to form a mixture of distorted edge and corner-sharing OK4Co trigonal bipyramids. In the third O2- site, O2- is bonded to four K1+ and one Co3+ atom to form a mixture of distorted edge and corner-sharing OK4Co trigonal bipyramids.