DOI: 10.17188/1699267
title: Materials Data on Dy4FeSe7 by Materials Project

description: Dy4FeSe7 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded to seven Se2- atoms to form distorted DySe7 pentagonal bipyramids that share corners with four DySe6 octahedra, corners with four equivalent FeSe6 octahedra, an edgeedge with one FeSe6 octahedra, edges with three equivalent DySe6 octahedra, edges with two equivalent DySe7 pentagonal bipyramids, and faces with two equivalent DySe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 18–75°. There are a spread of Dy–Se bond distances ranging from 2.87–3.20 Å. In the second Dy3+ site, Dy3+ is bonded to seven Se2- atoms to form distorted DySe7 pentagonal bipyramids that share corners with two equivalent FeSe6 octahedra, corners with six DySe6 octahedra, edges with four DySe6 octahedra, edges with two equivalent DySe7 pentagonal bipyramids, and faces with two equivalent DySe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 23–68°. There are a spread of Dy–Se bond distances ranging from 2.83–3.11 Å. In the third Dy3+ site, Dy3+ is bonded to six Se2- atoms to form DySe6 octahedra that share a cornercorner with one DySe6 octahedra, a cornercorner with one FeSe6 octahedra, corners with four DySe7 pentagonal bipyramids, edges with two equivalent DySe6 octahedra, and edges with six DySe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 50–51°. There are a spread of Dy–Se bond distances ranging from 2.78–2.85 Å. In the fourth Dy3+ site, Dy3+ is bonded to six Se2- atoms to form DySe6 octahedra that share a cornercorner with one DySe6 octahedra, corners with two equivalent FeSe6 octahedra, corners with six DySe7 pentagonal bipyramids, edges with two equivalent DySe6 octahedra, edges with three equivalent FeSe6 octahedra, and an edgeedge with one DySe7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 5–50°. There are a spread of Dy–Se bond distances ranging from 2.80–2.91 Å. Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with three DySe6 octahedra, corners with six DySe7 pentagonal bipyramids, edges with two equivalent FeSe6 octahedra, edges with three equivalent DySe6 octahedra, and an edgeedge with one DySe7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 5–51°. There are a spread of Fe–Se bond distances ranging from 2.60–2.76 Å. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four Dy3+ and one Fe2+ atom to form distorted SeDy4Fe trigonal bipyramids that share corners with five SeDy3Fe tetrahedra, corners with two equivalent SeDy5 trigonal bipyramids, edges with two equivalent SeDy3Fe2 square pyramids, an edgeedge with one SeDy4 tetrahedra, and edges with two equivalent SeDy4Fe trigonal bipyramids. In the second Se2- site, Se2- is bonded to three Dy3+ and two equivalent Fe2+ atoms to form distorted SeDy3Fe2 square pyramids that share corners with five SeDy3Fe tetrahedra, corners with two equivalent SeDy5 trigonal bipyramids, edges with two equivalent SeDy3Fe2 square pyramids, an edgeedge with one SeDy3Fe tetrahedra, and edges with three SeDy4Fe trigonal bipyramids. In the third Se2- site, Se2- is bonded to five Dy3+ atoms to form distorted SeDy5 trigonal bipyramids that share corners with two equivalent SeDy3Fe2 square pyramids, corners with four equivalent SeDy3Fe tetrahedra, corners with two equivalent SeDy4Fe trigonal bipyramids, an edgeedge with one SeDy3Fe2 square pyramid, edges with three SeDy3Fe tetrahedra, and edges with two equivalent SeDy5 trigonal bipyramids. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to five Dy3+ atoms. In the fifth Se2- site, Se2- is bonded to three Dy3+ and one Fe2+ atom to form distorted SeDy3Fe tetrahedra that share corners with four equivalent SeDy3Fe2 square pyramids, corners with three SeDy3Fe tetrahedra, corners with five SeDy4Fe trigonal bipyramids, an edgeedge with one SeDy3Fe2 square pyramid, and an edgeedge with one SeDy5 trigonal bipyramid. In the sixth Se2- site, Se2- is bonded to four Dy3+ atoms to form distorted SeDy4 tetrahedra that share a cornercorner with one SeDy3Fe2 square pyramid, corners with three SeDy3Fe tetrahedra, corners with four equivalent SeDy4Fe trigonal bipyramids, and edges with three SeDy4Fe trigonal bipyramids. In the seventh Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to two equivalent Dy3+ and two equivalent Fe2+ atoms.