Materials Data on NbCr2Fe3(PO4)6 by Materials Project

Abstract

NbCr2Fe3(PO4)6 crystallizes in the trigonal R3 space group. The structure is three-dimensional. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (1.95 Å) and three longer (2.08 Å) Nb–O bond lengths. There are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.14 Å) and three longer (2.44 Å) Cr–O bond lengths. In the second Cr3+ site, Cr3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.26 Å) and three longer (2.27 Å) Cr–O bond lengths. There are three inequivalent Fe+2.33+ sites. In the first Fe+2.33+ site, Fe+2.33+ is bonded to six O2- atoms to form distorted FeO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (1.93 Å) and three longer (2.16 Å) Fe–O bond lengths. In the second Fe+2.33+ site, Fe+2.33+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (1.97 Å) and three longer (2.14 Å) Fe–O bond lengths. In the third Fe+2.33+ site, Fe+2.33+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (1.97 Å) and three longer (2.09 Å) Fe–O bond lengths. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with three FeO6 octahedra. The corner-sharing octahedra tilt angles range from 21–51°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one NbO6 octahedra and corners with three FeO6 octahedra. The corner-sharing octahedra tilt angles range from 27–47°. There are a spread of P–O bond distances ranging from 1.53–1.60 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe+2.33+ and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Cr3+, one Fe+2.33+, and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Nb5+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Cr3+, one Fe+2.33+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe+2.33+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Nb5+, one Cr3+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Cr3+, one Fe+2.33+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe+2.33+ and one P5+ atom.