Materials Data on K2Hf2O5 by Materials Project
K2Hf2O5 crystallizes in the orthorhombic Pnna space group. The structure is three-dimensional. K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.58–3.23 Å. Hf4+ is bonded to six O2- atoms to form a mixture of edge, face, and corner-sharing HfO6 octahedra. The corner-sharing octahedra tilt angles range from 12–48°. There are a spread of Hf–O bond distances ranging from 2.02–2.25 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four equivalent K1+ and two equivalent Hf4+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+ and three equivalent Hf4+ atoms. In the third O2- site, O2- is bonded in a distorted tetrahedral geometry to two equivalent K1+ and two equivalent Hf4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent K1+ and two equivalent Hf4+ atoms.