Materials Data on Co2As2O7 by Materials Project
Co2As2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with six AsO4 tetrahedra and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.04–2.23 Å. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share a cornercorner with one CoO6 octahedra, corners with five AsO4 tetrahedra, edges with two CoO6 octahedra, and an edgeedge with one AsO4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Co–O bond distances ranging from 2.07–2.41 Å. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with six AsO4 tetrahedra and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.06–2.21 Å. In the fourth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share a cornercorner with one CoO6 octahedra, corners with six AsO4 tetrahedra, and edges with two CoO6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Co–O bond distances ranging from 1.99–2.17 Å. In the fifth Co2+ site, Co2+ is bonded to six O2- atoms to form distorted CoO6 octahedra that share corners with six AsO4 tetrahedra and edges with three CoO6 octahedra. There are a spread of Co–O bond distances ranging from 2.02–2.33 Å. There are five inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six CoO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–59°. There are a spread of As–O bond distances ranging from 1.66–1.80 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six CoO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–64°. There are a spread of As–O bond distances ranging from 1.70–1.74 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form distorted AsO4 tetrahedra that share corners with five CoO6 octahedra, a cornercorner with one AsO4 tetrahedra, and an edgeedge with one CoO6 octahedra. The corner-sharing octahedra tilt angles range from 37–68°. There are a spread of As–O bond distances ranging from 1.72–1.79 Å. In the fourth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six CoO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–66°. There are a spread of As–O bond distances ranging from 1.71–1.77 Å. In the fifth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with six CoO6 octahedra and a cornercorner with one AsO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–61°. There are a spread of As–O bond distances ranging from 1.71–1.75 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Co2+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Co2+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Co2+ and two As5+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent As5+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two As5+ atoms. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co2+ and one As5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Co2+ and one As5+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Co2+ and one As5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Co2+ and one As5+ atom. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Co2+ and one As5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom. In the eighteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Co2+ and one As5+ atom.