DOI: 10.17188/1674213
title: Materials Data on Dy4MgS7 by Materials Project

description: MgDy4S7 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Mg2+ is bonded to six S2- atoms to form MgS6 octahedra that share corners with three DyS6 octahedra, corners with two equivalent DyS7 pentagonal bipyramids, edges with two equivalent MgS6 octahedra, and edges with three equivalent DyS6 octahedra. The corner-sharing octahedra tilt angles range from 2–56°. There are a spread of Mg–S bond distances ranging from 2.56–2.68 Å. There are four inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Dy–S bond distances ranging from 2.71–3.08 Å. In the second Dy3+ site, Dy3+ is bonded to seven S2- atoms to form distorted DyS7 pentagonal bipyramids that share corners with two equivalent MgS6 octahedra, corners with six DyS6 octahedra, edges with four DyS6 octahedra, and faces with two equivalent DyS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 22–68°. There are a spread of Dy–S bond distances ranging from 2.70–3.00 Å. In the third Dy3+ site, Dy3+ is bonded to six S2- atoms to form DyS6 octahedra that share a cornercorner with one MgS6 octahedra, a cornercorner with one DyS6 octahedra, corners with two equivalent DyS7 pentagonal bipyramids, edges with two equivalent DyS6 octahedra, and edges with three equivalent DyS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Dy–S bond distances ranging from 2.67–2.73 Å. In the fourth Dy3+ site, Dy3+ is bonded to six S2- atoms to form DyS6 octahedra that share a cornercorner with one DyS6 octahedra, corners with two equivalent MgS6 octahedra, corners with four equivalent DyS7 pentagonal bipyramids, edges with two equivalent DyS6 octahedra, edges with three equivalent MgS6 octahedra, and an edgeedge with one DyS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 2–53°. There are a spread of Dy–S bond distances ranging from 2.68–2.78 Å. There are seven inequivalent S2- sites. In the first S2- site, S2- is bonded to one Mg2+ and four Dy3+ atoms to form distorted SDy4Mg trigonal bipyramids that share corners with five SDy3Mg tetrahedra, corners with four SDy5 trigonal bipyramids, an edgeedge with one SDy4 tetrahedra, and edges with five SDy4Mg trigonal bipyramids. In the second S2- site, S2- is bonded to two equivalent Mg2+ and three Dy3+ atoms to form distorted SDy3Mg2 trigonal bipyramids that share corners with five SDy3Mg tetrahedra, corners with four SDy5 trigonal bipyramids, an edgeedge with one SDy3Mg tetrahedra, and edges with five SDy4Mg trigonal bipyramids. In the third S2- site, S2- is bonded to five Dy3+ atoms to form distorted SDy5 trigonal bipyramids that share corners with four equivalent SDy3Mg tetrahedra, corners with six SDy4Mg trigonal bipyramids, edges with three SDy3Mg tetrahedra, and edges with six SDy3Mg2 trigonal bipyramids. In the fourth S2- site, S2- is bonded to five Dy3+ atoms to form distorted SDy5 trigonal bipyramids that share corners with four equivalent SDy4 tetrahedra, corners with six SDy4Mg trigonal bipyramids, edges with three SDy3Mg tetrahedra, and edges with six SDy4Mg trigonal bipyramids. In the fifth S2- site, S2- is bonded to one Mg2+ and three Dy3+ atoms to form distorted SDy3Mg tetrahedra that share corners with three SDy3Mg tetrahedra, corners with nine SDy4Mg trigonal bipyramids, and edges with four SDy3Mg2 trigonal bipyramids. In the sixth S2- site, S2- is bonded to four Dy3+ atoms to form distorted SDy4 tetrahedra that share corners with three SDy3Mg tetrahedra, corners with nine SDy4Mg trigonal bipyramids, and edges with four SDy4Mg trigonal bipyramids. In the seventh S2- site, S2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two equivalent Dy3+ atoms.