Materials Data on Cr(FeAs3)2 by Materials Project
Cr(FeAs3)2 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. Cr4+ is bonded to six As+1.67- atoms to form CrAs6 octahedra that share corners with eight FeAs6 octahedra and edges with two equivalent CrAs6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are five shorter (2.47 Å) and one longer (2.49 Å) Cr–As bond lengths. There are three inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six As+1.67- atoms to form a mixture of edge and corner-sharing FeAs6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are two shorter (2.39 Å) and four longer (2.40 Å) Fe–As bond lengths. In the second Fe3+ site, Fe3+ is bonded to six As+1.67- atoms to form FeAs6 octahedra that share corners with four equivalent CrAs6 octahedra, corners with four equivalent FeAs6 octahedra, and edges with two equivalent FeAs6 octahedra. The corner-sharing octahedra tilt angles range from 52–53°. There are a spread of Fe–As bond distances ranging from 2.37–2.41 Å. In the third Fe3+ site, Fe3+ is bonded to six As+1.67- atoms to form FeAs6 octahedra that share corners with eight equivalent CrAs6 octahedra and edges with two equivalent FeAs6 octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are two shorter (2.35 Å) and four longer (2.37 Å) Fe–As bond lengths. There are six inequivalent As+1.67- sites. In the first As+1.67- site, As+1.67- is bonded in a 4-coordinate geometry to one Cr4+ and two equivalent Fe3+ atoms. In the second As+1.67- site, As+1.67- is bonded in a 4-coordinate geometry to one Cr4+ and two equivalent Fe3+ atoms. In the third As+1.67- site, As+1.67- is bonded in a 4-coordinate geometry to three Fe3+ atoms. In the fourth As+1.67- site, As+1.67- is bonded in a 4-coordinate geometry to two equivalent Cr4+ and one Fe3+ atom. In the fifth As+1.67- site, As+1.67- is bonded in a 4-coordinate geometry to two equivalent Cr4+ and one Fe3+ atom. In the sixth As+1.67- site, As+1.67- is bonded in a 4-coordinate geometry to three Fe3+ atoms.