DOE OSTI2020
Ca5(CuO2)6 crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. there are five inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form edge-sharing CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.35–2.41 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form edge-sharing CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.34–2.42 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted edge-sharing CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.54 Å. In the fourth Ca2+ site, Ca2+ is bonded to six O2- atoms to form distorted edge-sharing CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.57 Å. In the fifth Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.83 Å. There are eight inequivalent Cu+2.33+ sites. In the first Cu+2.33+ site, Cu+2.33+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.97 Å) and two longer (2.01 Å) Cu–O bond length. In the second Cu+2.33+ site, Cu+2.33+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.90–1.92 Å. In the third Cu+2.33+ site, Cu+2.33+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.93–1.99 Å. In the fourth Cu+2.33+ site, Cu+2.33+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.87 Å) and two longer (1.89 Å) Cu–O bond length. In the fifth Cu+2.33+ site, Cu+2.33+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.97 Å) and two longer (2.00 Å) Cu–O bond length. In the sixth Cu+2.33+ site, Cu+2.33+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is one shorter (1.90 Å) and three longer (1.91 Å) Cu–O bond length. In the seventh Cu+2.33+ site, Cu+2.33+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.93–1.99 Å. In the eighth Cu+2.33+ site, Cu+2.33+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.87 Å) and two longer (1.89 Å) Cu–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two Cu+2.33+ atoms. In the second O2- site, O2- is bonded to three Ca2+ and two Cu+2.33+ atoms to form distorted OCa3Cu2 trigonal bipyramids that share corners with three OCa3Cu2 square pyramids, a cornercorner with one OCa3Cu2 trigonal bipyramid, a cornercorner with one OCa2Cu2 trigonal pyramid, an edgeedge with one OCa3Cu2 square pyramid, an edgeedge with one OCa3Cu2 trigonal bipyramid, and an edgeedge with one OCa2Cu2 trigonal pyramid. In the third O2- site, O2- is bonded to two Ca2+ and two equivalent Cu+2.33+ atoms to form distorted OCa2Cu2 trigonal pyramids that share a cornercorner with one OCa3Cu2 square pyramid, a cornercorner with one OCa3Cu2 trigonal bipyramid, a cornercorner with one OCa2Cu2 trigonal pyramid, an edgeedge with one OCa3Cu2 trigonal bipyramid, and an edgeedge with one OCa2Cu2 trigonal pyramid. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and two Cu+2.33+ atoms. In the fifth O2- site, O2- is bonded to three Ca2+ and two Cu+2.33+ atoms to form distorted OCa3Cu2 trigonal bipyramids that share corners with three OCa3Cu2 square pyramids, a cornercorner with one OCa3Cu2 trigonal bipyramid, a cornercorner with one OCa2Cu2 trigonal pyramid, an edgeedge with one OCa3Cu2 square pyramid, an edgeedge with one OCa3Cu2 trigonal bipyramid, and an edgeedge with one OCa2Cu2 trigonal pyramid. In the sixth O2- site, O2- is bonded to two Ca2+ and two equivalent Cu+2.33+ atoms to form distorted OCa2Cu2 trigonal pyramids that share a cornercorner with one OCa3Cu2 square pyramid, a cornercorner with one OCa3Cu2 trigonal bipyramid, a cornercorner with one OCa2Cu2 trigonal pyramid, an edgeedge with one OCa3Cu2 trigonal bipyramid, and an edgeedge with one OCa2Cu2 trigonal pyramid. In the seventh O2- site, O2- is bonded to three Ca2+ and two equivalent Cu+2.33+ atoms to form distorted OCa3Cu2 square pyramids that share corners with three OCa3Cu2 trigonal bipyramids, a cornercorner with one OCa2Cu2 trigonal pyramid, edges with two OCa3Cu2 square pyramids, and an edgeedge with one OCa3Cu2 trigonal bipyramid. In the eighth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two Cu+2.33+ atoms. In the ninth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Ca2+ and two Cu+2.33+ atoms. In the tenth O2- site, O2- is bonded to three Ca2+ and two equivalent Cu+2.33+ atoms to form distorted OCa3Cu2 square pyramids that share corners with three OCa3Cu2 trigonal bipyramids, a cornercorner with one OCa2Cu2 trigonal pyramid, edges with two OCa3Cu2 square pyramids, and an edgeedge with one OCa3Cu2 trigonal bipyramid. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and two Cu+2.33+ atoms. In the twelfth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Ca2+ and two Cu+2.33+ atoms.