Materials Data on NaGdTiNbO6F by Materials Project

Abstract

NaGdTiNbO6F crystallizes in the tetragonal P4_322 space group. The structure is three-dimensional. Na1+ is bonded to six O2- and two equivalent F1- atoms to form distorted NaO6F2 hexagonal bipyramids that share edges with two equivalent NaO6F2 hexagonal bipyramids, edges with two equivalent TiO6 octahedra, and edges with four equivalent NbO6 octahedra. There are two shorter (2.57 Å) and four longer (2.74 Å) Na–O bond lengths. Both Na–F bond lengths are 2.24 Å. Gd3+ is bonded in a 8-coordinate geometry to six O2- and two equivalent F1- atoms. There are a spread of Gd–O bond distances ranging from 2.36–2.77 Å. Both Gd–F bond lengths are 2.28 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four equivalent NbO6 octahedra, and edges with two equivalent NaO6F2 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 45–47°. There are a spread of Ti–O bond distances ranging from 1.93–2.02 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra, corners with four equivalent TiO6 octahedra, and edges with four equivalent NaO6F2 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 40–47°. There are four shorter (2.00 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 equivalent Na1+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Gd3+, one Ti4+, and one Nb5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Gd3+, one Ti4+, and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Gd3+ and two equivalent Ti4+ atoms. F1- is bonded to two equivalent Na1+ and two equivalent Gd3+ atoms to form corner-sharing FNa2Gd2 tetrahedra.