Materials Data on FeMo3As4 by Materials Project

Mo3FeAs4 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are three inequivalent Mo+3.33+ sites. In the first Mo+3.33+ site, Mo+3.33+ is bonded to six As3- atoms to form distorted MoAs6 pentagonal pyramids that share corners with eight equivalent MoAs6 octahedra, corners with four equivalent FeAs6 pentagonal pyramids, edges with six MoAs6 pentagonal pyramids, and faces with two equivalent FeAs6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 41–59°. There are a spread of Mo–As bond distances ranging from 2.51–2.63 Å. In the second Mo+3.33+ site, Mo+3.33+ is bonded to six As3- atoms to form distorted MoAs6 octahedra that share corners with twelve MoAs6 pentagonal pyramids, edges with two equivalent MoAs6 octahedra, edges with four equivalent FeAs6 pentagonal pyramids, and faces with two equivalent MoAs6 pentagonal pyramids. There are a spread of Mo–As bond distances ranging from 2.51–2.67 Å. In the third Mo+3.33+ site, Mo+3.33+ is bonded to six As3- atoms to form distorted MoAs6 pentagonal pyramids that share corners with four equivalent MoAs6 octahedra, corners with eight equivalent FeAs6 pentagonal pyramids, edges with six MoAs6 pentagonal pyramids, and faces with two equivalent MoAs6 octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Mo–As bond distances ranging from 2.58–2.73 Å. Fe2+ is bonded to six As3- atoms to form distorted FeAs6 pentagonal pyramids that share corners with twelve MoAs6 pentagonal pyramids, edges with four equivalent MoAs6 octahedra, edges with two equivalent FeAs6 pentagonal pyramids, and faces with two equivalent MoAs6 pentagonal pyramids. There are a spread of Fe–As bond distances ranging from 2.46–2.69 Å. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded in a 6-coordinate geometry to five Mo+3.33+ and one Fe2+ atom. In the second As3- site, As3- is bonded in a 1-coordinate geometry to five Mo+3.33+ and one Fe2+ atom. In the third As3- site, As3- is bonded in a 2-coordinate geometry to four Mo+3.33+ and two equivalent Fe2+ atoms. In the fourth As3- site, As3- is bonded in a 2-coordinate geometry to four Mo+3.33+ and two equivalent Fe2+ atoms.