Materials Data on CoAsSe by Materials Project

Abstract

CoAsSe is Marcasite-derived structured and crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are two inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to two equivalent As1- and four equivalent Se2- atoms to form CoAs2Se4 octahedra that share corners with eight equivalent CoAs4Se2 octahedra, corners with two equivalent AsCo3As tetrahedra, and edges with two equivalent CoAs2Se4 octahedra. The corner-sharing octahedral tilt angles are 57°. Both Co–As bond lengths are 2.39 Å. All Co–Se bond lengths are 2.37 Å. In the second Co3+ site, Co3+ is bonded to four equivalent As1- and two equivalent Se2- atoms to form CoAs4Se2 octahedra that share corners with eight equivalent CoAs2Se4 octahedra, corners with four equivalent AsCo3As tetrahedra, and edges with two equivalent CoAs4Se2 octahedra. The corner-sharing octahedral tilt angles are 57°. All Co–As bond lengths are 2.40 Å. Both Co–Se bond lengths are 2.32 Å. As1- is bonded to three Co3+ and one As1- atom to form distorted AsCo3As tetrahedra that share corners with three CoAs2Se4 octahedra, corners with five equivalent AsCo3As tetrahedra, and an edgeedge with one AsCo3As tetrahedra. The corner-sharing octahedra tilt angles range from 73–79°. The As–As bond length is 2.47 Å. Se2- is bonded in a 3-coordinate geometry to three Co3+ atoms.