Materials Data on K2Na4Co2O5 by Materials Project
K2Na4Co2O5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 1-coordinate geometry to three O2- atoms. There are a spread of K–O bond distances ranging from 2.75–3.23 Å. There are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.67 Å. In the second Na1+ site, Na1+ is bonded to four O2- atoms to form distorted corner-sharing NaO4 trigonal pyramids. There are a spread of Na–O bond distances ranging from 2.44–2.47 Å. Co2+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.82 Å) and one longer (1.92 Å) Co–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 7-coordinate geometry to two equivalent K1+, four Na1+, and one Co2+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one Co2+ atom. In the third O2- site, O2- is bonded in an octahedral geometry to two equivalent K1+, two equivalent Na1+, and two equivalent Co2+ atoms.