Materials Data on HfB2O5 by Materials Project
HfB2O5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Hf4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Hf–O bond distances ranging from 2.08–2.43 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.43–1.54 Å. In the second B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.51 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Hf4+ and two B3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Hf4+ and one B3+ atom. In the third O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Hf4+ and two B3+ atoms. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Hf4+ and one B3+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Hf4+ and two B3+ atoms.