Materials Data on FeCo16NiS16 by Materials Project
FeCo16NiS16 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Fe2+ is bonded to six S2- atoms to form FeS6 octahedra that share corners with twenty-four CoS4 tetrahedra. There are two shorter (2.32 Å) and four longer (2.33 Å) Fe–S bond lengths. There are two inequivalent Co+1.75+ sites. In the first Co+1.75+ site, Co+1.75+ is bonded to four S2- atoms to form CoS4 tetrahedra that share a cornercorner with one FeS6 octahedra, corners with two equivalent NiS6 octahedra, corners with six CoS4 tetrahedra, and edges with three equivalent CoS4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Co–S bond distances ranging from 2.11–2.22 Å. In the second Co+1.75+ site, Co+1.75+ is bonded to four S2- atoms to form CoS4 tetrahedra that share a cornercorner with one NiS6 octahedra, corners with two equivalent FeS6 octahedra, corners with six CoS4 tetrahedra, and edges with three equivalent CoS4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of Co–S bond distances ranging from 2.11–2.21 Å. Ni2+ is bonded to six S2- atoms to form NiS6 octahedra that share corners with twenty-four CoS4 tetrahedra. All Ni–S bond lengths are 2.39 Å. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to one Fe2+ and four equivalent Co+1.75+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent Co+1.75+ and one Ni2+ atom. In the third S2- site, S2- is bonded in a 5-coordinate geometry to one Fe2+ and four equivalent Co+1.75+ atoms. In the fourth S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent Co+1.75+ and one Ni2+ atom. In the fifth S2- site, S2- is bonded in a tetrahedral geometry to four Co+1.75+ atoms.