DOI: 10.17188/1681724
title: Materials Data on Dy9Al5Se21 by Materials Project

description: Dy9Al5Se21 crystallizes in the trigonal R3 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 Se2- atoms. There are a spread of Dy–Se bond distances ranging from 2.88–3.14 Å. In the second Dy3+ site, Dy3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Dy–Se bond distances ranging from 2.87–3.19 Å. In the third Dy3+ site, Dy3+ is bonded to seven Se2- atoms to form distorted DySe7 pentagonal bipyramids that share a cornercorner with one AlSe6 octahedra, corners with three DySe7 pentagonal bipyramids, corners with two AlSe4 tetrahedra, an edgeedge with one AlSe6 octahedra, and an edgeedge with one AlSe4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. There are a spread of Dy–Se bond distances ranging from 2.89–3.18 Å. In the fourth Dy3+ site, Dy3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Dy–Se bond distances ranging from 2.86–3.26 Å. In the fifth Dy3+ site, Dy3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Dy–Se bond distances ranging from 2.88–3.16 Å. In the sixth Dy3+ site, Dy3+ is bonded to seven Se2- atoms to form distorted DySe7 pentagonal bipyramids that share a cornercorner with one AlSe6 octahedra, corners with three DySe7 pentagonal bipyramids, corners with two AlSe4 tetrahedra, an edgeedge with one AlSe6 octahedra, and an edgeedge with one AlSe4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There are a spread of Dy–Se bond distances ranging from 2.90–3.08 Å. There are six inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Se2- atoms to form AlSe4 tetrahedra that share corners with two DySe7 pentagonal bipyramids and an edgeedge with one DySe7 pentagonal bipyramid. There are a spread of Al–Se bond distances ranging from 2.37–2.40 Å. In the second Al3+ site, Al3+ is bonded to four Se2- atoms to form AlSe4 tetrahedra that share corners with two DySe7 pentagonal bipyramids and an edgeedge with one DySe7 pentagonal bipyramid. There are a spread of Al–Se bond distances ranging from 2.38–2.40 Å. In the third Al3+ site, Al3+ is bonded to six Se2- atoms to form AlSe6 octahedra that share corners with three equivalent DySe7 pentagonal bipyramids and a faceface with one AlSe6 octahedra. There are three shorter (2.57 Å) and three longer (2.62 Å) Al–Se bond lengths. In the fourth Al3+ site, Al3+ is bonded to six Se2- atoms to form distorted AlSe6 octahedra that share edges with three equivalent DySe7 pentagonal bipyramids and a faceface with one AlSe6 octahedra. There are three shorter (2.46 Å) and three longer (2.80 Å) Al–Se bond lengths. In the fifth Al3+ site, Al3+ is bonded to six Se2- atoms to form distorted AlSe6 octahedra that share edges with three equivalent DySe7 pentagonal bipyramids and a faceface with one AlSe6 octahedra. There are three shorter (2.45 Å) and three longer (2.81 Å) Al–Se bond lengths. In the sixth Al3+ site, Al3+ is bonded to six Se2- atoms to form AlSe6 octahedra that share corners with three equivalent DySe7 pentagonal bipyramids and a faceface with one AlSe6 octahedra. There are three shorter (2.57 Å) and three longer (2.62 Å) Al–Se bond lengths. There are fourteen inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Dy3+ and one Al3+ atom to form distorted SeDy3Al tetrahedra that share corners with three SeDy3Al2 square pyramids and corners with three SeDy3Al trigonal pyramids. In the second Se2- site, Se2- is bonded to three Dy3+ and one Al3+ atom to form distorted SeDy3Al tetrahedra that share corners with three SeDy3Al2 square pyramids and corners with three SeDy3Al trigonal pyramids. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to three Dy3+ and one Al3+ atom. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Dy3+ and one Al3+ atom. In the fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Dy3+ and one Al3+ atom. In the sixth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Dy3+ and one Al3+ atom. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Dy3+ and one Al3+ atom. In the eighth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Dy3+ and one Al3+ atom. In the ninth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Dy3+ and one Al3+ atom. In the tenth Se2- site, Se2- is bonded to three Dy3+ and two Al3+ atoms to form distorted SeDy3Al2 square pyramids that share corners with three SeDy3Al tetrahedra, a cornercorner with one SeDy3Al trigonal pyramid, edges with two equivalent SeDy3Al trigonal pyramids, and faces with two equivalent SeDy3Al2 square pyramids. In the eleventh Se2- site, Se2- is bonded to three Dy3+ and one Al3+ atom to form distorted SeDy3Al trigonal pyramids that share a cornercorner with one SeDy3Al2 square pyramid, corners with three SeDy3Al tetrahedra, edges with two equivalent SeDy3Al2 square pyramids, and edges with two equivalent SeDy3Al trigonal pyramids. In the twelfth Se2- site, Se2- is bonded to three Dy3+ and two Al3+ atoms to form distorted SeDy3Al2 square pyramids that share corners with three SeDy3Al tetrahedra, a cornercorner with one SeDy3Al trigonal pyramid, edges with two equivalent SeDy3Al trigonal pyramids, and faces with two equivalent SeDy3Al2 square pyramids. In the thirteenth Se2- site, Se2- is bonded to three Dy3+ and one Al3+ atom to form distorted SeDy3Al trigonal pyramids that share a cornercorner with one SeDy3Al2 square pyramid, corners with three SeDy3Al tetrahedra, edges with two equivalent SeDy3Al2 square pyramids, and edges with two equivalent SeDy3Al trigonal pyramids. In the fourteenth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Dy3+ and one Al3+ atom.