Materials Data on Co2As2O5 by Materials Project
Co2As2O5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to five O2- atoms to form CoO5 trigonal bipyramids that share a cornercorner with one CoO4 tetrahedra and edges with two CoO6 octahedra. There are a spread of Co–O bond distances ranging from 1.98–2.30 Å. In the second Co2+ site, Co2+ is bonded to four O2- atoms to form distorted CoO4 tetrahedra that share corners with two CoO6 octahedra, a cornercorner with one CoO5 trigonal bipyramid, and an edgeedge with one CoO4 tetrahedra. The corner-sharing octahedra tilt angles range from 70–75°. There are a spread of Co–O bond distances ranging from 1.99–2.04 Å. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share a cornercorner with one CoO4 tetrahedra, edges with four CoO6 octahedra, and an edgeedge with one CoO5 trigonal bipyramid. There are a spread of Co–O bond distances ranging from 1.99–2.23 Å. In the fourth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one CoO4 tetrahedra, edges with four CoO6 octahedra, and an edgeedge with one CoO5 trigonal bipyramid. There are a spread of Co–O bond distances ranging from 2.06–2.20 Å. There are four inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.79–1.88 Å. In the second As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.80–1.85 Å. In the third As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.82 Å) and one longer (1.83 Å) As–O bond length. In the fourth As3+ site, As3+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of As–O bond distances ranging from 1.80–1.85 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Co2+ and one As3+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As3+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As3+ atom. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to one Co2+ and two As3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co2+ and one As3+ atom. In the sixth O2- site, O2- is bonded in a trigonal planar geometry to two Co2+ and one As3+ atom. In the seventh O2- site, O2- is bonded to three Co2+ and one As3+ atom to form a mixture of corner and edge-sharing OCo3As trigonal pyramids. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two As3+ atoms. In the ninth O2- site, O2- is bonded to three Co2+ and one As3+ atom to form a mixture of corner and edge-sharing OCo3As trigonal pyramids. In the tenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to three Co2+ and one As3+ atom.