Materials Data on NaMgFe(SO4)3 by Materials Project

Abstract

NaMgFe(SO4)3 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.45 Å. In the second Na1+ site, Na1+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.56 Å. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent SO4 tetrahedra. There are three shorter (2.04 Å) and three longer (2.09 Å) Mg–O bond lengths. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent SO4 tetrahedra. There are three shorter (1.99 Å) and three longer (2.07 Å) Fe–O bond lengths. S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 24–40°. There are a spread of S–O bond distances ranging from 1.46–1.51 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one S6+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Mg2+, and one S6+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Fe3+, and one S6+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one S6+ atom.