Materials Data on CaFe2Sb2(PO4)6 by Materials Project

Abstract

CaFe2Sb2(PO4)6 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Ca2+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Ca–O bond lengths are 2.44 Å. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent PO4 tetrahedra. There are three shorter (1.96 Å) and three longer (2.08 Å) Fe–O bond lengths. Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with six equivalent PO4 tetrahedra. There is three shorter (1.98 Å) and three longer (1.99 Å) Sb–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent FeO6 octahedra and corners with two equivalent SbO6 octahedra. The corner-sharing octahedra tilt angles range from 28–48°. There are a spread of P–O bond distances ranging from 1.51–1.59 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sb5+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Sb5+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Fe3+, and one P5+ atom.