Materials Data on Ba2HfO4 by Materials Project
Ba2HfO4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.69–2.97 Å. Hf4+ is bonded to six O2- atoms to form corner-sharing HfO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.10 Å) and two longer (2.11 Å) Hf–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five equivalent Ba2+ and one Hf4+ atom to form a mixture of distorted corner and edge-sharing OBa5Hf octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the second O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two equivalent Hf4+ atoms.