DOE OSTI2020
Sr9Nd3Cu12(PbO4)8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are five inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.64–2.79 Å. In the second Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.61–2.81 Å. In the third Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.60–2.80 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.61–2.81 Å. In the fifth Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight O2- atoms. All Sr–O bond lengths are 2.57 Å. There are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.47–2.51 Å. In the second Nd3+ site, Nd3+ is bonded in a body-centered cubic geometry to eight O2- atoms. All Nd–O bond lengths are 2.48 Å. There are six inequivalent Cu+1.75+ sites. In the first Cu+1.75+ site, Cu+1.75+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one PbO5 square pyramid and corners with four CuO5 square pyramids. There are a spread of Cu–O bond distances ranging from 1.93–2.30 Å. In the second Cu+1.75+ site, Cu+1.75+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one PbO5 square pyramid and corners with four CuO5 square pyramids. There are four shorter (1.95 Å) and one longer (2.30 Å) Cu–O bond lengths. In the third Cu+1.75+ site, Cu+1.75+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one PbO5 square pyramid and corners with four CuO5 square pyramids. There are a spread of Cu–O bond distances ranging from 1.94–2.30 Å. In the fourth Cu+1.75+ site, Cu+1.75+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one PbO5 square pyramid and corners with four CuO5 square pyramids. There are four shorter (1.94 Å) and one longer (2.31 Å) Cu–O bond lengths. In the fifth Cu+1.75+ site, Cu+1.75+ is bonded in a linear geometry to two O2- atoms. Both Cu–O bond lengths are 1.86 Å. In the sixth Cu+1.75+ site, Cu+1.75+ is bonded in a linear geometry to two O2- atoms. Both Cu–O bond lengths are 1.86 Å. There are four inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to five O2- atoms to form PbO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with four PbO5 square pyramids, and edges with four PbO5 square pyramids. There are one shorter (2.18 Å) and four longer (2.73 Å) Pb–O bond lengths. In the second Pb2+ site, Pb2+ is bonded to five O2- atoms to form PbO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with four PbO5 square pyramids, and edges with four PbO5 square pyramids. There are one shorter (2.18 Å) and four longer (2.73 Å) Pb–O bond lengths. In the third Pb2+ site, Pb2+ is bonded to five O2- atoms to form PbO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with four PbO5 square pyramids, and edges with four PbO5 square pyramids. There are a spread of Pb–O bond distances ranging from 2.18–2.74 Å. In the fourth Pb2+ site, Pb2+ is bonded to five O2- atoms to form PbO5 square pyramids that share a cornercorner with one CuO5 square pyramid, corners with four PbO5 square pyramids, and edges with four PbO5 square pyramids. There are a spread of Pb–O bond distances ranging from 2.17–2.74 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two Sr2+, two Nd3+, and two Cu+1.75+ atoms. In the second O2- site, O2- is bonded in a 6-coordinate geometry to two Sr2+, two Nd3+, and two Cu+1.75+ atoms. In the third O2- site, O2- is bonded to three Sr2+, one Nd3+, and two Cu+1.75+ atoms to form a mixture of distorted edge, face, and corner-sharing OSr3NdCu2 octahedra. The corner-sharing octahedra tilt angles range from 0–66°. In the fourth O2- site, O2- is bonded to three Sr2+, one Nd3+, and two Cu+1.75+ atoms to form a mixture of distorted edge, face, and corner-sharing OSr3NdCu2 octahedra. The corner-sharing octahedra tilt angles range from 0–66°. In the fifth O2- site, O2- is bonded to one Sr2+, one Cu+1.75+, and four Pb2+ atoms to form distorted OSrCuPb4 octahedra that share corners with nine OSr3NdCu2 octahedra and edges with eight OSrCuPb4 octahedra. The corner-sharing octahedra tilt angles range from 0–46°. In the sixth O2- site, O2- is bonded to one Sr2+, one Cu+1.75+, and four Pb2+ atoms to form distorted OSrCuPb4 octahedra that share corners with seven OSr3NdCu2 octahedra and edges with eight OSrCuPb4 octahedra. The corner-sharing octahedra tilt angles range from 0–44°. In the seventh O2- site, O2- is bonded to one Sr2+, one Cu+1.75+, and four Pb2+ atoms to form a mixture of distorted edge and corner-sharing OSrCuPb4 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the eighth O2- site, O2- is bonded to one Sr2+, one Cu+1.75+, and four Pb2+ atoms to form distorted OSrCuPb4 octahedra that share corners with seven OSr3NdCu2 octahedra and edges with eight OSrCuPb4 octahedra. The corner-sharing octahedra tilt angles range from 0–44°. In the ninth O2- site, O2- is bonded to four Sr2+, one Cu+1.75+, and one Pb2+ atom to form distorted OSr4CuPb octahedra that share corners with eight OSr3NdCu2 octahedra, edges with eight OSrCuPb4 octahedra, and faces with two equivalent OSr3NdCu2 octahedra. The corner-sharing octahedra tilt angles range from 20–52°. In the tenth O2- site, O2- is bonded to four Sr2+, one Cu+1.75+, and one Pb2+ atom to form distorted OSr4CuPb octahedra that share corners with eight OSr3NdCu2 octahedra and edges with eight OSrCuPb4 octahedra. The corner-sharing octahedra tilt angles range from 20–53°. In the eleventh O2- site, O2- is bonded to four Sr2+, one Cu+1.75+, and one Pb2+ atom to form distorted OSr4CuPb octahedra that share corners with eight OSr3NdCu2 octahedra, edges with eight OSrCuPb4 octahedra, and faces with two equivalent OSr3NdCu2 octahedra. The corner-sharing octahedra tilt angles range from 20–52°. In the twelfth O2- site, O2- is bonded to four Sr2+, one Cu+1.75+, and one Pb2+ atom to form distorted OSr4CuPb octahedra that share corners with eight OSr3NdCu2 octahedra, edges with eight OSrCuPb4 octahedra, and faces with four OSr3NdCu2 octahedra. The corner-sharing octahedra tilt angles range from 20–51°.