Materials Data on FeNiSe4 by Materials Project

FeNiSe4 is pyrite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Fe3+ is bonded to six Se+1.75- atoms to form FeSe6 octahedra that share corners with four equivalent FeSe6 octahedra and corners with eight equivalent NiSe6 octahedra. The corner-sharing octahedra tilt angles range from 61–64°. There are a spread of Fe–Se bond distances ranging from 2.37–2.41 Å. Ni4+ is bonded to six Se+1.75- atoms to form NiSe6 octahedra that share corners with four equivalent NiSe6 octahedra and corners with eight equivalent FeSe6 octahedra. The corner-sharing octahedra tilt angles range from 62–65°. There are four shorter (2.46 Å) and two longer (2.49 Å) Ni–Se bond lengths. There are two inequivalent Se+1.75- sites. In the first Se+1.75- site, Se+1.75- is bonded in a 3-coordinate geometry to one Fe3+ and two equivalent Ni4+ atoms. In the second Se+1.75- site, Se+1.75- is bonded in a distorted trigonal planar geometry to two equivalent Fe3+ and one Ni4+ atom.