Materials Data on Na3(FeS2)2 by Materials Project

Abstract

Na3Fe2S4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with eight equivalent FeS4 tetrahedra, edges with two equivalent FeS4 tetrahedra, and faces with two equivalent NaS6 octahedra. There are a spread of Na–S bond distances ranging from 2.80–3.06 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to six S2- atoms. There are a spread of Na–S bond distances ranging from 2.83–3.47 Å. Fe+2.50+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with four equivalent NaS6 octahedra, an edgeedge with one NaS6 octahedra, and edges with two equivalent FeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 15–66°. There are a spread of Fe–S bond distances ranging from 2.25–2.29 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to four equivalent Na1+ and two equivalent Fe+2.50+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to five Na1+ and two equivalent Fe+2.50+ atoms. In the third S2- site, S2- is bonded in a 6-coordinate geometry to four Na1+ and two equivalent Fe+2.50+ atoms.