DOE OSTI2020
Dy3NbO7 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Dy–O bond distances ranging from 2.21–2.54 Å. In the second Dy3+ site, Dy3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Dy–O bond distances ranging from 2.10–2.59 Å. In the third Dy3+ site, Dy3+ is bonded to seven O2- atoms to form distorted DyO7 pentagonal bipyramids that share a cornercorner with one NbO6 octahedra and an edgeedge with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are a spread of Dy–O bond distances ranging from 2.22–2.47 Å. In the fourth Dy3+ site, Dy3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Dy–O bond distances ranging from 2.15–2.43 Å. In the fifth Dy3+ site, Dy3+ is bonded in a 6-coordinate geometry to seven O2- atoms. There are a spread of Dy–O bond distances ranging from 2.18–2.80 Å. In the sixth Dy3+ site, Dy3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Dy–O bond distances ranging from 2.13–2.69 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share a cornercorner with one DyO7 pentagonal bipyramid and an edgeedge with one DyO7 pentagonal bipyramid. There are a spread of Nb–O bond distances ranging from 1.93–2.35 Å. In the second Nb5+ site, Nb5+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Nb–O bond distances ranging from 1.91–2.40 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded to four Dy3+ atoms to form ODy4 tetrahedra that share corners with six ODy3Nb tetrahedra, edges with three ODy4 tetrahedra, and an edgeedge with one ODy3Nb trigonal pyramid. In the second O2- site, O2- is bonded to three Dy3+ and one Nb5+ atom to form distorted ODy3Nb tetrahedra that share corners with five ODy4 tetrahedra, edges with two ODy4 tetrahedra, and edges with two equivalent ODy3Nb trigonal pyramids. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Dy3+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded to four Dy3+ atoms to form ODy4 tetrahedra that share corners with six ODy4 tetrahedra, corners with two equivalent ODy3Nb trigonal pyramids, and edges with two ODy3Nb tetrahedra. In the fifth O2- site, O2- is bonded to four Dy3+ atoms to form ODy4 tetrahedra that share corners with four ODy4 tetrahedra, corners with two equivalent ODy3Nb trigonal pyramids, and edges with four ODy4 tetrahedra. In the sixth O2- site, O2- is bonded to three Dy3+ and one Nb5+ atom to form ODy3Nb tetrahedra that share corners with four ODy4 tetrahedra, a cornercorner with one ODy3Nb trigonal pyramid, and edges with two ODy4 tetrahedra. In the seventh O2- site, O2- is bonded to three Dy3+ and one Nb5+ atom to form distorted ODy3Nb tetrahedra that share corners with seven ODy3Nb tetrahedra, corners with two equivalent ODy3Nb trigonal pyramids, and an edgeedge with one ODy4 tetrahedra. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Dy3+ and two Nb5+ atoms. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two Dy3+ and one Nb5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to three Dy3+ and one Nb5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to three Dy3+ atoms. In the twelfth O2- site, O2- is bonded to three Dy3+ and one Nb5+ atom to form a mixture of distorted corner and edge-sharing ODy3Nb trigonal pyramids. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Dy3+ and two Nb5+ atoms. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to three Dy3+ and one Nb5+ atom.