Materials Data on Er3TaO7 by Materials Project

Abstract

Er3TaO7 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. there are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to seven O2- atoms to form distorted ErO7 pentagonal bipyramids that share corners with two equivalent TaO6 octahedra, a cornercorner with one ErO7 pentagonal bipyramid, edges with two equivalent TaO6 octahedra, and edges with three equivalent ErO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 42–49°. There are a spread of Er–O bond distances ranging from 2.19–2.44 Å. In the second Er3+ site, Er3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.31–2.87 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with four equivalent ErO7 pentagonal bipyramids, and edges with four equivalent ErO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. There are a spread of Ta–O bond distances ranging from 1.95–2.03 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Er3+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Er3+ and one Ta5+ atom. In the third O2- site, O2- is bonded to three Er3+ and one Ta5+ atom to form a mixture of distorted edge and corner-sharing OEr3Ta tetrahedra. In the fourth O2- site, O2- is bonded to four Er3+ atoms to form a mixture of edge and corner-sharing OEr4 tetrahedra. In the fifth O2- site, O2- is bonded to four Er3+ atoms to form a mixture of edge and corner-sharing OEr4 tetrahedra.