DOI: 10.17188/1683515
title: Materials Data on Sr4CeSm3Nb2(CuO5)4 by Materials Project

description: Sr4Sm3CeNb2(CuO5)4 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. there are four inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, faces with four equivalent NbO6 octahedra, and faces with four equivalent CuO5 square pyramids. There are a spread of Sr–O bond distances ranging from 2.80–2.97 Å. In the second Sr2+ site, Sr2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Sr–O bond distances ranging from 2.67–3.17 Å. In the third Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, faces with four equivalent NbO6 octahedra, and faces with four equivalent CuO5 square pyramids. There are a spread of Sr–O bond distances ranging from 2.80–3.03 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 12-coordinate geometry to eight O2- atoms. There are four shorter (2.65 Å) and four longer (2.83 Å) Sr–O bond lengths. There are three inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.31 Å) and four longer (2.67 Å) Sm–O bond lengths. In the second Sm3+ site, Sm3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.39 Å) and four longer (2.53 Å) Sm–O bond lengths. In the third Sm3+ site, Sm3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.31 Å) and four longer (2.68 Å) Sm–O bond lengths. Ce4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.31 Å) and four longer (2.53 Å) Ce–O bond lengths. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four equivalent NbO6 octahedra, corners with two CuO5 square pyramids, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There is five shorter (1.97 Å) and one longer (2.02 Å) Nb–O bond length. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with four equivalent NbO6 octahedra, corners with two CuO5 square pyramids, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 4°. There are a spread of Nb–O bond distances ranging from 1.95–2.04 Å. There are four inequivalent Cu+2.25+ sites. In the first Cu+2.25+ site, Cu+2.25+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one NbO6 octahedra, corners with four equivalent CuO5 square pyramids, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.98 Å) and one longer (2.16 Å) Cu–O bond lengths. In the second Cu+2.25+ site, Cu+2.25+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one NbO6 octahedra and corners with four equivalent CuO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.97 Å) and one longer (2.18 Å) Cu–O bond lengths. In the third Cu+2.25+ site, Cu+2.25+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one NbO6 octahedra, corners with four equivalent CuO5 square pyramids, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.98 Å) and one longer (2.16 Å) Cu–O bond lengths. In the fourth Cu+2.25+ site, Cu+2.25+ is bonded to five O2- atoms to form CuO5 square pyramids that share a cornercorner with one NbO6 octahedra and corners with four equivalent CuO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (1.97 Å) and one longer (2.22 Å) Cu–O bond lengths. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sm3+ and two equivalent Ce4+ atoms to form a mixture of edge and corner-sharing OCe2Sm2 tetrahedra. In the second O2- site, O2- is bonded to four Sm3+ atoms to form OSm4 tetrahedra that share corners with twelve OSr2Sm2Cu2 octahedra, corners with four equivalent OSm4 tetrahedra, edges with two OSr2Sm2Cu2 octahedra, and edges with four equivalent OSm4 tetrahedra. The corner-sharing octahedra tilt angles range from 11–69°. In the third O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Ce4+, and two equivalent Cu+2.25+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Sm3+, and two equivalent Cu+2.25+ atoms to form distorted OSr2Sm2Cu2 octahedra that share corners with two equivalent OSr2Sm2Cu2 octahedra, corners with six equivalent OSm4 tetrahedra, edges with two equivalent OSr2Sm2Cu2 octahedra, an edgeedge with one OSm4 tetrahedra, and faces with four equivalent OSr2Sm2Cu2 octahedra. The corner-sharing octahedral tilt angles are 5°. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, two equivalent Sm3+, and two equivalent Cu+2.25+ atoms. In the sixth O2- site, O2- is bonded to two equivalent Sr2+, two equivalent Sm3+, and two equivalent Cu+2.25+ atoms to form distorted OSr2Sm2Cu2 octahedra that share corners with two equivalent OSr2Sm2Cu2 octahedra, corners with six equivalent OSm4 tetrahedra, edges with two equivalent OSr2Sm2Cu2 octahedra, an edgeedge with one OSm4 tetrahedra, and faces with four equivalent OSr2Sm2Cu2 octahedra. The corner-sharing octahedral tilt angles are 3°. In the seventh O2- site, O2- is bonded in a linear geometry to four Sr2+ and two equivalent Nb5+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to two equivalent Sr2+ and two equivalent Nb5+ atoms. In the ninth O2- site, O2- is bonded to four equivalent Sr2+, one Nb5+, and one Cu+2.25+ atom to form a mixture of distorted edge and corner-sharing OSr4NbCu octahedra. The corner-sharing octahedral tilt angles are 10°. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Sr2+, one Nb5+, and one Cu+2.25+ atom. In the eleventh O2- site, O2- is bonded to four equivalent Sr2+, one Nb5+, and one Cu+2.25+ atom to form a mixture of distorted edge and corner-sharing OSr4NbCu octahedra. The corner-sharing octahedral tilt angles are 13°. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Sr2+, one Nb5+, and one Cu+2.25+ atom.