DOE OSTI2020
Ca3Cu6(AsO4)8 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.22–2.86 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six AsO4 tetrahedra and edges with two CuO5 trigonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.30–2.48 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six AsO4 tetrahedra and edges with two CuO5 trigonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.31–2.45 Å. There are six inequivalent Cu3+ sites. In the first Cu3+ site, Cu3+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with five AsO4 tetrahedra and an edgeedge with one CaO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.83–2.44 Å. In the second Cu3+ site, Cu3+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five AsO4 tetrahedra and an edgeedge with one CaO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.82–2.15 Å. In the third Cu3+ site, Cu3+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five AsO4 tetrahedra and an edgeedge with one CaO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.86–2.09 Å. In the fourth Cu3+ site, Cu3+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five AsO4 tetrahedra and an edgeedge with one CaO6 octahedra. There are a spread of Cu–O bond distances ranging from 1.82–2.08 Å. In the fifth Cu3+ site, Cu3+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.85–1.90 Å. In the sixth Cu3+ site, Cu3+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.85–1.91 Å. There are eight inequivalent As5+ sites. In the first As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with three CuO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–63°. There are a spread of As–O bond distances ranging from 1.69–1.75 Å. In the second As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with two CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 60°. There are a spread of As–O bond distances ranging from 1.64–1.81 Å. In the third As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with two CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 58°. There are a spread of As–O bond distances ranging from 1.65–1.80 Å. In the fourth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with two CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 54°. There are a spread of As–O bond distances ranging from 1.66–1.82 Å. In the fifth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with three CuO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–60°. There are a spread of As–O bond distances ranging from 1.70–1.77 Å. In the sixth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share a cornercorner with one CaO6 octahedra and corners with two CuO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 56°. There are a spread of As–O bond distances ranging from 1.66–1.79 Å. In the seventh As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with three CuO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 51–59°. There are a spread of As–O bond distances ranging from 1.69–1.77 Å. In the eighth As5+ site, As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent CaO6 octahedra and corners with three CuO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 54–62°. There are a spread of As–O bond distances ranging from 1.69–1.75 Å. There are thirty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one As5+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one As5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one As5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one As5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the eleventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the twelfth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cu3+ and one As5+ atom. In the fourteenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one As5+ atom. In the fifteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Cu3+, and one As5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cu3+ and one As5+ atom. In the eighteenth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and one As5+ atom. In the nineteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Ca2+ and one As5+ atom. In the twentieth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the twenty-first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the twenty-second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the twenty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the twenty-fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cu3+ and one As5+ atom. In the twenty-sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the twenty-seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Cu3+, and one As5+ atom. In the twenty-eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one As5+ atom. In the twenty-ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Cu3+, and one As5+ atom. In the thirtieth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the thirty-first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, two Cu3+, and one As5+ atom. In the thirty-second O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom.