Materials Data on HoBO3 by Materials Project

Abstract

HoBO3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.25–2.48 Å. In the second Ho3+ site, Ho3+ is bonded to eight O2- atoms to form HoO8 hexagonal bipyramids that share corners with two equivalent HoO8 hexagonal bipyramids, corners with two equivalent BO4 tetrahedra, and edges with four equivalent BO4 tetrahedra. There are a spread of Ho–O bond distances ranging from 2.28–2.44 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share corners with two BO4 tetrahedra and edges with two equivalent HoO8 hexagonal bipyramids. There is two shorter (1.45 Å) and two longer (1.51 Å) B–O bond length. In the second B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share corners with two equivalent HoO8 hexagonal bipyramids and corners with two equivalent BO4 tetrahedra. There is two shorter (1.46 Å) and two longer (1.52 Å) B–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ho3+ and two B3+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one B3+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Ho3+ and one B3+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ho3+ and two equivalent B3+ atoms.