DOE OSTI2020
FeNi2S4 is Spinel structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Fe3+ is bonded to four equivalent S2- atoms to form FeS4 tetrahedra that share corners with twelve equivalent NiS6 octahedra. The corner-sharing octahedral tilt angles are 56°. All Fe–S bond lengths are 2.12 Å. Ni+2.50+ is bonded to six equivalent S2- atoms to form NiS6 octahedra that share corners with six equivalent FeS4 tetrahedra and edges with six equivalent NiS6 octahedra. All Ni–S bond lengths are 2.30 Å. S2- is bonded in a distorted rectangular see-saw-like geometry to one Fe3+ and three equivalent Ni+2.50+ atoms.