DOE OSTI2020
Ca10Pr4Cu24O41 crystallizes in the orthorhombic Cccm space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.72 Å. In the second Ca2+ site, Ca2+ is bonded to seven O2- atoms to form distorted CaO7 pentagonal bipyramids that share corners with four equivalent PrO7 pentagonal bipyramids and a faceface with one CaO7 pentagonal bipyramid. There are a spread of Ca–O bond distances ranging from 2.33–2.71 Å. In the third 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 2.36–3.04 Å. Pr+3.50+ is bonded to seven O2- atoms to form distorted PrO7 pentagonal bipyramids that share corners with two equivalent CaO7 pentagonal bipyramids and a faceface with one PrO7 pentagonal bipyramid. There are a spread of Pr–O bond distances ranging from 2.34–2.57 Å. There are ten inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.91–2.03 Å. In the second Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.95 Å) and two longer (1.97 Å) Cu–O bond length. In the third Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.90–2.00 Å. In the fourth Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.91 Å) and two longer (1.92 Å) Cu–O bond length. In the fifth Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.91 Å) and two longer (1.92 Å) Cu–O bond length. In the sixth Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There is two shorter (1.96 Å) and two longer (1.97 Å) Cu–O bond length. In the seventh Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.90–2.02 Å. In the eighth Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.86–2.00 Å. In the ninth Cu2+ site, Cu2+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.99 Å. In the tenth Cu2+ site, Cu2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.93 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ca2+ and three Cu2+ atoms to form OCa2Cu3 trigonal bipyramids that share corners with two OPr2Cu3 trigonal bipyramids, edges with three OCa2Cu3 trigonal bipyramids, and a faceface with one OCa4Cu2 octahedra. In the second O2- site, O2- is bonded to two equivalent Pr+3.50+ and three Cu2+ atoms to form distorted OPr2Cu3 trigonal bipyramids that share a cornercorner with one OCa4Cu2 octahedra, corners with two OCa2Cu3 trigonal bipyramids, corners with two equivalent OCaPrCu2 trigonal pyramids, edges with three OCa2Cu3 trigonal bipyramids, and a faceface with one OCa2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Pr+3.50+, and two Cu2+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Ca2+ and three Cu2+ atoms to form OCa2Cu3 trigonal bipyramids that share a cornercorner with one OCa2Pr2Cu2 octahedra, corners with two OCa2Cu3 trigonal bipyramids, corners with two equivalent OCaPrCu2 trigonal pyramids, edges with three OPr2Cu3 trigonal bipyramids, and faces with two OCa4Cu2 octahedra. The corner-sharing octahedral tilt angles are 6°. In the fifth O2- site, O2- is bonded to four Ca2+ and two equivalent Cu2+ atoms to form distorted OCa4Cu2 octahedra that share corners with two equivalent OPr2Cu3 trigonal bipyramids, corners with two equivalent OCaPrCu2 trigonal pyramids, an edgeedge with one OCa4Cu2 octahedra, and faces with four OCa2Cu3 trigonal bipyramids. In the sixth O2- site, O2- is bonded in a distorted see-saw-like geometry to one Ca2+, one Pr+3.50+, and two Cu2+ atoms. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to three Ca2+ and two equivalent Cu2+ atoms. In the eighth O2- site, O2- is bonded to two equivalent Ca2+ and three Cu2+ atoms to form OCa2Cu3 trigonal bipyramids that share a cornercorner with one OCa4Cu2 octahedra, corners with two equivalent OPr2Cu3 trigonal bipyramids, edges with three OCa2Cu3 trigonal bipyramids, and faces with two equivalent OCa2Pr2Cu2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the ninth O2- site, O2- is bonded to one Ca2+, one Pr+3.50+, and two Cu2+ atoms to form distorted OCaPrCu2 trigonal pyramids that share corners with three OCa2Pr2Cu2 octahedra, corners with four OPr2Cu3 trigonal bipyramids, and an edgeedge with one OCaPrCu2 trigonal pyramid. The corner-sharing octahedra tilt angles range from 45–88°. In the tenth O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ca2+, two equivalent Pr+3.50+, and two equivalent Cu2+ atoms. In the eleventh O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Ca2+ and two equivalent Cu2+ atoms. In the twelfth O2- site, O2- is bonded in a distorted square co-planar geometry to two Ca2+ and two Cu2+ atoms. In the thirteenth O2- site, O2- is bonded to two equivalent Ca2+, two equivalent Pr+3.50+, and two equivalent Cu2+ atoms to form distorted OCa2Pr2Cu2 octahedra that share corners with two equivalent OCa2Cu3 trigonal bipyramids, corners with two equivalent OCaPrCu2 trigonal pyramids, an edgeedge with one OCa2Pr2Cu2 octahedra, and faces with four OPr2Cu3 trigonal bipyramids. In the fourteenth O2- site, O2- is bonded to four equivalent Ca2+ and two equivalent Cu2+ atoms to form distorted OCa4Cu2 octahedra that share corners with two equivalent OCa2Cu3 trigonal bipyramids, corners with four equivalent OCaPrCu2 trigonal pyramids, edges with two equivalent OCa4Cu2 octahedra, and faces with four equivalent OCa2Cu3 trigonal bipyramids.