Materials Data on Co8As3O16 by Materials Project

Abstract

Co8As3O16 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Co+2.12+ sites. In the first Co+2.12+ site, Co+2.12+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six equivalent CoO6 octahedra, edges with two equivalent AsO6 octahedra, and edges with six CoO6 octahedra. The corner-sharing octahedra tilt angles range from 8–17°. There are four shorter (2.13 Å) and two longer (2.18 Å) Co–O bond lengths. In the second Co+2.12+ site, Co+2.12+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent CoO6 octahedra, corners with three equivalent AsO4 tetrahedra, an edgeedge with one AsO6 octahedra, and edges with five CoO6 octahedra. The corner-sharing octahedra tilt angles range from 8–17°. There are a spread of Co–O bond distances ranging from 2.06–2.19 Å. In the third Co+2.12+ site, Co+2.12+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent AsO4 tetrahedra, an edgeedge with one AsO6 octahedra, and edges with six CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.06–2.12 Å. There are two inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to six O2- atoms to form AsO6 octahedra that share edges with ten CoO6 octahedra. There is four shorter (1.87 Å) and two longer (1.88 Å) As–O bond length. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with nine CoO6 octahedra. The corner-sharing octahedra tilt angles range from 53–57°. There are a spread of As–O bond distances ranging from 1.72–1.77 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co+2.12+ and one As5+ atom. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co+2.12+ and one As5+ atom. In the third O2- site, O2- is bonded to four Co+2.12+ and one As5+ atom to form OCo4As square pyramids that share corners with three equivalent OCo4As square pyramids and edges with three equivalent OCo5 square pyramids. In the fourth O2- site, O2- is bonded to five Co+2.12+ atoms to form OCo5 square pyramids that share corners with two equivalent OCo5 square pyramids and edges with three equivalent OCo4As square pyramids. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Co+2.12+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co+2.12+ and one As5+ atom.