Materials Data on FeAsSe by Materials Project
FeAs(Se) crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Fe3+ is bonded to three equivalent As1- and three equivalent Se2- atoms to form FeAs3Se3 octahedra that share corners with eight equivalent FeAs3Se3 octahedra, corners with three equivalent AsFe3Se tetrahedra, corners with three equivalent SeFe3As tetrahedra, and edges with two equivalent FeAs3Se3 octahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Fe–As bond distances ranging from 2.40–2.43 Å. There are two shorter (2.32 Å) and one longer (2.34 Å) Fe–Se bond lengths. As1- is bonded to three equivalent Fe3+ and one Se2- atom to form distorted AsFe3Se tetrahedra that share corners with three equivalent FeAs3Se3 octahedra, corners with four equivalent AsFe3Se tetrahedra, corners with nine equivalent SeFe3As tetrahedra, and an edgeedge with one AsFe3Se tetrahedra. The corner-sharing octahedra tilt angles range from 68–74°. The As–Se bond length is 2.55 Å. Se2- is bonded to three equivalent Fe3+ and one As1- atom to form distorted SeFe3As tetrahedra that share corners with three equivalent FeAs3Se3 octahedra, corners with four equivalent SeFe3As tetrahedra, corners with nine equivalent AsFe3Se tetrahedra, and an edgeedge with one SeFe3As tetrahedra. The corner-sharing octahedra tilt angles range from 76–79°.