Materials Data on Fe3NiAs8 by Materials Project
Fe3NiAs8 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six As+1.38- atoms to form FeAs6 octahedra that share corners with four equivalent FeAs6 octahedra, corners with four equivalent NiAs6 octahedra, and edges with two equivalent FeAs6 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Fe–As bond distances ranging from 2.32–2.39 Å. In the second Fe3+ site, Fe3+ is bonded to six As+1.38- atoms to form a mixture of corner and edge-sharing FeAs6 octahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are two shorter (2.37 Å) and four longer (2.39 Å) Fe–As bond lengths. Ni2+ is bonded to six As+1.38- atoms to form NiAs6 octahedra that share corners with eight equivalent FeAs6 octahedra and edges with two equivalent NiAs6 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. All Ni–As bond lengths are 2.41 Å. There are four inequivalent As+1.38- sites. In the first As+1.38- site, As+1.38- is bonded in a 4-coordinate geometry to three Fe3+ atoms. In the second As+1.38- site, As+1.38- is bonded in a 4-coordinate geometry to one Fe3+ and two equivalent Ni2+ atoms. In the third As+1.38- site, As+1.38- is bonded in a 4-coordinate geometry to three Fe3+ atoms. In the fourth As+1.38- site, As+1.38- is bonded in a 4-coordinate geometry to two equivalent Fe3+ and one Ni2+ atom.