DOE OSTI2020
Mg2V6Cu4O21 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 2.01–2.07 Å. In the second Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 2.02–2.06 Å. In the third Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 2.03–2.06 Å. In the fourth Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 2.01–2.06 Å. There are twelve inequivalent V5+ sites. In the first V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, corners with two CuO5 trigonal bipyramids, and corners with three MgO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.68–1.81 Å. In the second V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, corners with two equivalent MgO5 trigonal bipyramids, and corners with three CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.67–1.79 Å. In the third V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, corners with two equivalent MgO5 trigonal bipyramids, and corners with three CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.67–1.79 Å. In the fourth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, corners with two CuO5 trigonal bipyramids, and corners with three MgO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.67–1.81 Å. In the fifth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, a cornercorner with one MgO5 trigonal bipyramid, and corners with four CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.69–1.81 Å. In the sixth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, a cornercorner with one MgO5 trigonal bipyramid, and corners with four CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.69–1.82 Å. In the seventh V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, corners with two MgO5 trigonal bipyramids, and corners with three CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.70–1.82 Å. In the eighth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, a cornercorner with one MgO5 trigonal bipyramid, and corners with four CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.69–1.81 Å. In the ninth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, a cornercorner with one MgO5 trigonal bipyramid, and corners with four CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.69–1.81 Å. In the tenth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, corners with two MgO5 trigonal bipyramids, and corners with three CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.70–1.81 Å. In the eleventh V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, a cornercorner with one MgO5 trigonal bipyramid, and corners with four CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.70–1.80 Å. In the twelfth V5+ site, V5+ is bonded to four O2- atoms to form VO4 tetrahedra that share a cornercorner with one VO4 tetrahedra, a cornercorner with one MgO5 trigonal bipyramid, and corners with four CuO5 trigonal bipyramids. There are a spread of V–O bond distances ranging from 1.70–1.80 Å. There are eight inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.91–2.36 Å. In the second Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.91–2.36 Å. In the third Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent MgO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.93–2.30 Å. In the fourth Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent MgO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.93–2.31 Å. In the fifth Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent MgO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.92–2.30 Å. In the sixth Cu2+ site, Cu2+ is bonded to five O2- atoms to form CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent MgO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.93–2.28 Å. In the seventh Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.93–2.34 Å. In the eighth Cu2+ site, Cu2+ is bonded to five O2- atoms to form distorted CuO5 trigonal bipyramids that share corners with five VO4 tetrahedra and edges with two equivalent CuO5 trigonal bipyramids. There are a spread of Cu–O bond distances ranging from 1.93–2.34 Å. There are forty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one V5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one V5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one V5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Mg2+ and one V5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one V5+ and one Cu2+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one V5+ and two Cu2+ atoms. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one V5+ and two Cu2+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the seventeenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the eighteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the nineteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one V5+, and one Cu2+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to one V5+ and two Cu2+ atoms. In the twenty-first O2- site, O2- is bonded in a 3-coordinate geometry to one V5+ and two Cu2+ atoms. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one V5+, and one Cu2+ atom. In the twenty-third O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one V5+, and one Cu2+ atom. In the twenty-fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one V5+, and one Cu2+ atom. In the twenty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the twenty-sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one V5+ and two Cu2+ atoms. In the twenty-seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one V5+ and two Cu2+ atoms. In the twenty-eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the twenty-ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the thirtieth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the thirty-first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the thirty-second O2- site, O2- is bonded in a distorted trigonal planar geometry to one V5+ and two Cu2+ atoms. In the thirty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to one V5+ and two Cu2+ atoms. In the thirty-fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the thirty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the thirty-sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one V5+, and one Cu2+ atom. In the thirty-seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two V5+ atoms. In the thirty-eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two V5+ atoms. In the thirty-ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two V5+ atoms. In the fortieth O2- site, O2- is bonded in a bent 150 degrees geometry to two V5+ atoms. In the forty-first O2- site, O2- is bonded in a bent 150 degrees geometry to two V5+ atoms. In the forty-second O2- site, O2- is bonded in a bent 150 degrees geometry to two V5+ atoms.