Materials Data on NaFe(SO4)2 by Materials Project
NaFe(SO4)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Na1+ is bonded in a distorted hexagonal planar geometry to six O2- atoms. There are two shorter (2.45 Å) and four longer (2.66 Å) Na–O bond lengths. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six equivalent SO4 tetrahedra. There are two shorter (1.99 Å) and four longer (2.04 Å) Fe–O bond lengths. S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with three equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 36–45°. There are a spread of S–O bond distances ranging from 1.45–1.51 Å. There are three 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 2-coordinate geometry to one Na1+ 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.