Materials Data on NdTa2O6F by Materials Project

Abstract

NdFTa2O6 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. Nd3+ is bonded to six O2- and two equivalent F1- atoms to form distorted NdO6F2 hexagonal bipyramids that share edges with two equivalent NdO6F2 hexagonal bipyramids and edges with six TaO6 octahedra. There are four shorter (2.59 Å) and two longer (2.63 Å) Nd–O bond lengths. Both Nd–F bond lengths are 2.25 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and edges with two equivalent NdO6F2 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 33–43°. There is two shorter (1.98 Å) and four longer (2.01 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and edges with four equivalent NdO6F2 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–47°. There is four shorter (1.98 Å) and two longer (2.01 Å) Ta–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Nd3+ and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Nd3+ and two Ta5+ atoms. F1- is bonded in a bent 120 degrees geometry to two equivalent Nd3+ atoms.