DOE OSTI2020
Er2Sb2O7 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are seven inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.32–2.71 Å. In the second Er3+ site, Er3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.17–2.76 Å. In the third Er3+ site, Er3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Er–O bond distances ranging from 2.20–2.61 Å. In the fourth Er3+ site, Er3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.32–2.71 Å. In the fifth Er3+ site, Er3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Er–O bond distances ranging from 2.19–2.61 Å. In the sixth Er3+ site, Er3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.16–2.75 Å. In the seventh Er3+ site, Er3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Er–O bond distances ranging from 2.19–2.61 Å. There are seven inequivalent Sb4+ sites. In the first Sb4+ site, Sb4+ is bonded to six O2- atoms to form distorted corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There are a spread of Sb–O bond distances ranging from 2.25–2.32 Å. In the second Sb4+ site, Sb4+ is bonded in a 2-coordinate geometry to six O2- atoms. There are a spread of Sb–O bond distances ranging from 2.07–2.71 Å. In the third Sb4+ site, Sb4+ is bonded to six O2- atoms to form corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 38–60°. There are a spread of Sb–O bond distances ranging from 1.98–2.03 Å. In the fourth Sb4+ site, Sb4+ is bonded to six O2- atoms to form corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 37–59°. There are a spread of Sb–O bond distances ranging from 1.98–2.03 Å. In the fifth Sb4+ site, Sb4+ is bonded to six O2- atoms to form corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 37–60°. There are a spread of Sb–O bond distances ranging from 1.98–2.03 Å. In the sixth Sb4+ site, Sb4+ is bonded to six O2- atoms to form distorted corner-sharing SbO6 octahedra. The corner-sharing octahedra tilt angles range from 58–60°. There are a spread of Sb–O bond distances ranging from 2.26–2.31 Å. In the seventh Sb4+ site, Sb4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sb–O bond distances ranging from 2.07–2.71 Å. There are twenty-one inequivalent O2- sites. In the first O2- site, O2- is bonded to three Er3+ and one Sb4+ atom to form OEr3Sb tetrahedra that share corners with six OEr2Sb2 tetrahedra and edges with four OEr3Sb tetrahedra. In the second O2- site, O2- is bonded to two Er3+ and two Sb4+ atoms to form distorted OEr2Sb2 tetrahedra that share corners with ten OEr2Sb2 tetrahedra and edges with three OEr3Sb tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Er3+ and two Sb4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and two Sb4+ atoms. In the fifth O2- site, O2- is bonded to three Er3+ and one Sb4+ atom to form a mixture of edge and corner-sharing OEr3Sb tetrahedra. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Er3+ and two Sb4+ atoms. In the seventh O2- site, O2- is bonded to three Er3+ and one Sb4+ atom to form a mixture of edge and corner-sharing OEr3Sb tetrahedra. In the eighth O2- site, O2- is bonded to two Er3+ and two Sb4+ atoms to form a mixture of distorted edge and corner-sharing OEr2Sb2 tetrahedra. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and two equivalent Sb4+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two Er3+ and two Sb4+ atoms. In the eleventh O2- site, O2- is bonded to two Er3+ and two Sb4+ atoms to form a mixture of distorted edge and corner-sharing OEr2Sb2 tetrahedra. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Er3+ and two Sb4+ atoms. In the thirteenth O2- site, O2- is bonded to three Er3+ and one Sb4+ atom to form a mixture of edge and corner-sharing OEr3Sb tetrahedra. In the fourteenth O2- site, O2- is bonded to two Er3+ and two Sb4+ atoms to form distorted OEr2Sb2 tetrahedra that share corners with eight OEr2Sb2 tetrahedra and edges with three OEr3Sb tetrahedra. In the fifteenth O2- site, O2- is bonded to two Er3+ and two Sb4+ atoms to form a mixture of distorted edge and corner-sharing OEr2Sb2 tetrahedra. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Er3+ and two Sb4+ atoms. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Er3+ and two Sb4+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Er3+ and two Sb4+ atoms. In the nineteenth O2- site, O2- is bonded to two Er3+ and two Sb4+ atoms to form distorted OEr2Sb2 tetrahedra that share corners with ten OEr3Sb tetrahedra and edges with three OEr2Sb2 tetrahedra. In the twentieth O2- site, O2- is bonded to three Er3+ and one Sb4+ atom to form a mixture of edge and corner-sharing OEr3Sb tetrahedra. In the twenty-first O2- site, O2- is bonded to three Er3+ and one Sb4+ atom to form a mixture of edge and corner-sharing OEr3Sb tetrahedra.