Materials Data on K3NaOs2O9 by Materials Project
K3NaOs2O9 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve O2- atoms to form distorted KO12 cuboctahedra that share corners with twelve KO12 cuboctahedra, faces with six equivalent KO12 cuboctahedra, faces with two equivalent NaO6 octahedra, and faces with six equivalent OsO6 octahedra. There are six shorter (3.00 Å) and six longer (3.05 Å) K–O bond lengths. In the second K1+ site, K1+ is bonded to twelve O2- atoms to form distorted KO12 cuboctahedra that share corners with nine KO12 cuboctahedra, corners with three equivalent OsO6 octahedra, faces with seven KO12 cuboctahedra, faces with three equivalent NaO6 octahedra, and faces with four equivalent OsO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of K–O bond distances ranging from 2.92–3.31 Å. Na1+ is bonded to six equivalent O2- atoms to form NaO6 octahedra that share corners with six equivalent OsO6 octahedra and faces with eight KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 6°. All Na–O bond lengths are 2.32 Å. Os7+ is bonded to six O2- atoms to form distorted OsO6 octahedra that share corners with three equivalent KO12 cuboctahedra, corners with three equivalent NaO6 octahedra, faces with seven KO12 cuboctahedra, and a faceface with one OsO6 octahedra. The corner-sharing octahedral tilt angles are 6°. There is three shorter (1.81 Å) and three longer (2.03 Å) Os–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four K1+ and two equivalent Os7+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Na1+, and one Os7+ atom.