Materials Data on K2Rh2O5 by Materials Project
K2Rh2O5 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to eight equivalent O2- atoms to form distorted KO8 hexagonal bipyramids that share corners with eight equivalent KO12 cuboctahedra, edges with four equivalent KO8 hexagonal bipyramids, edges with eight equivalent RhO5 square pyramids, and faces with two equivalent KO12 cuboctahedra. All K–O bond lengths are 2.78 Å. In the second K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with four equivalent KO12 cuboctahedra, corners with eight equivalent KO8 hexagonal bipyramids, faces with four equivalent KO12 cuboctahedra, faces with two equivalent KO8 hexagonal bipyramids, and faces with eight equivalent RhO5 square pyramids. There are four shorter (2.75 Å) and eight longer (3.06 Å) K–O bond lengths. Rh4+ is bonded to five O2- atoms to form RhO5 square pyramids that share corners with five equivalent RhO5 square pyramids, edges with four equivalent KO8 hexagonal bipyramids, and faces with four equivalent KO12 cuboctahedra. There is four shorter (1.98 Å) and one longer (2.00 Å) Rh–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four K1+ and two equivalent Rh4+ atoms. In the second O2- site, O2- is bonded to four equivalent K1+ and two equivalent Rh4+ atoms to form a mixture of edge and corner-sharing OK4Rh2 octahedra. The corner-sharing octahedral tilt angles are 0°.