Materials Data on Sm2ScNbO7 by Materials Project

Abstract

Sm2ScNbO7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to eight O2- atoms to form distorted SmO8 hexagonal bipyramids that share edges with two equivalent SmO8 hexagonal bipyramids, edges with two equivalent ScO6 octahedra, and edges with four equivalent NbO6 octahedra. There are a spread of Sm–O bond distances ranging from 2.26–2.65 Å. In the second Sm3+ site, Sm3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.32–2.60 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 SmO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 51–58°. There are two shorter (2.12 Å) and four longer (2.13 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 SmO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–51°. There are four shorter (2.00 Å) and two longer (2.03 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 equivalent Sm3+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded to two equivalent Sm3+ and two equivalent Sc3+ atoms to form distorted OSm2Sc2 tetrahedra that share corners with six OSm2Sc2 tetrahedra and an edgeedge with one OSm4 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Sm3+, one Sc3+, and one Nb5+ atom. In the fourth O2- site, O2- is bonded to four Sm3+ atoms to form a mixture of edge and corner-sharing OSm4 tetrahedra.