Materials Data on Na2Sr2Nb4O13 by Materials Project

Abstract

Na2Sr2Nb4O13 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. Na1+ is bonded to seven O2- atoms to form distorted NaO7 hexagonal pyramids that share a cornercorner with one NaO7 hexagonal pyramid, corners with two equivalent SrO7 hexagonal pyramids, an edgeedge with one NaO7 hexagonal pyramid, edges with two equivalent SrO7 hexagonal pyramids, and edges with six NbO6 octahedra. There are a spread of Na–O bond distances ranging from 2.15–2.77 Å. Sr2+ is bonded to seven O2- atoms to form distorted SrO7 hexagonal pyramids that share a cornercorner with one SrO7 hexagonal pyramid, corners with two equivalent NaO7 hexagonal pyramids, an edgeedge with one SrO7 hexagonal pyramid, edges with two equivalent NaO7 hexagonal pyramids, and edges with six NbO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.18–2.74 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra, edges with two equivalent NaO7 hexagonal pyramids, and edges with four equivalent SrO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 39–43°. There are a spread of Nb–O bond distances ranging from 2.00–2.03 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six NbO6 octahedra, edges with two equivalent SrO7 hexagonal pyramids, and edges with four equivalent NaO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 36–42°. There are one shorter (2.00 Å) and five longer (2.02 Å) Nb–O bond lengths. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Sr2+, and two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two equivalent Nb5+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Sr2+, and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a tetrahedral geometry to two equivalent Na1+ and two equivalent Sr2+ atoms.