Materials Data on Na2Fe3S4 by Materials Project
Na2Fe3S4 crystallizes in the monoclinic Cm 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 eleven FeS4 tetrahedra, edges with six NaS6 octahedra, and edges with four FeS4 tetrahedra. There are a spread of Na–S bond distances ranging from 2.79–2.96 Å. In the second Na1+ site, Na1+ is bonded to six S2- atoms to form NaS6 octahedra that share corners with seven FeS4 tetrahedra, edges with six NaS6 octahedra, and edges with five FeS4 tetrahedra. There are a spread of Na–S bond distances ranging from 2.79–2.96 Å. There are three inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with six NaS6 octahedra, corners with two equivalent FeS4 tetrahedra, edges with three NaS6 octahedra, and edges with three FeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 21–51°. There are a spread of Fe–S bond distances ranging from 2.15–2.19 Å. In the second Fe2+ site, Fe2+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with six NaS6 octahedra, corners with six FeS4 tetrahedra, edges with three NaS6 octahedra, and an edgeedge with one FeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 24–54°. There are a spread of Fe–S bond distances ranging from 2.15–2.21 Å. In the third Fe2+ site, Fe2+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with six NaS6 octahedra, corners with six FeS4 tetrahedra, edges with three NaS6 octahedra, and edges with two equivalent FeS4 tetrahedra. The corner-sharing octahedra tilt angles range from 27–52°. There are a spread of Fe–S bond distances ranging from 2.18–2.28 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three Na1+ and three Fe2+ atoms to form distorted edge-sharing SNa3Fe3 octahedra. In the second S2- site, S2- is bonded in a 5-coordinate geometry to three Na1+ and two Fe2+ atoms. In the third S2- site, S2- is bonded in a 7-coordinate geometry to three Na1+ and four Fe2+ atoms. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to three Na1+ and three Fe2+ atoms.