Materials Data on Sm3NbO7 by Materials Project

Abstract

Sm3NbO7 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to seven O2- atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent NbO6 octahedra, a cornercorner with one SmO7 pentagonal bipyramid, edges with two equivalent NbO6 octahedra, and edges with three equivalent SmO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 42–48°. There are a spread of Sm–O bond distances ranging from 2.28–2.54 Å. In the second Sm3+ site, Sm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sm–O bond distances ranging from 2.38–2.96 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with four equivalent SmO7 pentagonal bipyramids, and edges with four equivalent SmO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 40°. There are a spread of Nb–O bond distances ranging from 1.97–2.06 Å. There are five 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 four Sm3+ atoms to form a mixture of corner and edge-sharing OSm4 tetrahedra. In the third O2- site, O2- is bonded in a 3-coordinate geometry to three Sm3+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded to four Sm3+ atoms to form a mixture of corner and edge-sharing OSm4 tetrahedra. In the fifth O2- site, O2- is bonded to three Sm3+ and one Nb5+ atom to form a mixture of distorted corner and edge-sharing OSm3Nb tetrahedra.