Materials Data on Ho2ScNbO7 by Materials Project

Abstract

Ho2ScNbO7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to eight O2- atoms to form distorted HoO8 hexagonal bipyramids that share edges with two equivalent HoO8 hexagonal bipyramids, edges with two equivalent ScO6 octahedra, and edges with four equivalent NbO6 octahedra. There are a spread of Ho–O bond distances ranging from 2.21–2.56 Å. In the second Ho3+ site, Ho3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.29–2.52 Å. Sc3+ is bonded to six O2- atoms to form ScO6 octahedra that share corners with two equivalent ScO6 octahedra, corners with four equivalent NbO6 octahedra, and edges with two equivalent HoO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 53–60°. There are two shorter (2.10 Å) and four longer (2.11 Å) Sc–O bond lengths. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with four equivalent ScO6 octahedra, and edges with four equivalent HoO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 46–53°. There are four shorter (1.99 Å) and two longer (2.02 Å) Nb–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Ho3+, one Sc3+, and one Nb5+ atom. In the second O2- site, O2- is bonded to two equivalent Ho3+ and two equivalent Sc3+ atoms to form OHo2Sc2 tetrahedra that share corners with six OHo2Sc2 tetrahedra and an edgeedge with one OHo4 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+ and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded to four Ho3+ atoms to form a mixture of edge and corner-sharing OHo4 tetrahedra.