Materials Data on K2Na4Be2O5 by Materials Project
K2Na4Be2O5 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are one shorter (2.71 Å) and four longer (2.82 Å) K–O bond lengths. There are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four equivalent O2- atoms to form distorted corner-sharing NaO4 tetrahedra. All Na–O bond lengths are 2.42 Å. In the second 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 2.28–2.49 Å. Be2+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.57 Å) and one longer (1.59 Å) Be–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, four Na1+, and one Be2+ atom. In the second O2- site, O2- is bonded in a distorted octahedral geometry to two equivalent K1+, two equivalent Na1+, and two equivalent Be2+ atoms.