DOE OSTI2020
Dy4CeS7 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent Dy sites. In the first Dy site, Dy is bonded to seven S atoms to form distorted DyS7 pentagonal bipyramids that share corners with four DyS6 octahedra, corners with four equivalent CeS6 octahedra, an edgeedge with one CeS6 octahedra, edges with three equivalent DyS6 octahedra, edges with two equivalent DyS7 pentagonal bipyramids, and faces with two equivalent DyS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 21–65°. There are a spread of Dy–S bond distances ranging from 2.74–2.94 Å. In the second Dy site, Dy is bonded to seven S atoms to form distorted DyS7 pentagonal bipyramids that share corners with two equivalent CeS6 octahedra, corners with six DyS6 octahedra, edges with four DyS6 octahedra, edges with two equivalent DyS7 pentagonal bipyramids, and faces with two equivalent DyS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 22–69°. There are a spread of Dy–S bond distances ranging from 2.75–2.95 Å. In the third Dy site, Dy is bonded to six S atoms to form DyS6 octahedra that share a cornercorner with one DyS6 octahedra, a cornercorner with one CeS6 octahedra, corners with four DyS7 pentagonal bipyramids, edges with two equivalent DyS6 octahedra, and edges with six DyS7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 58°. There are a spread of Dy–S bond distances ranging from 2.68–2.77 Å. In the fourth Dy site, Dy is bonded to six S atoms to form DyS6 octahedra that share a cornercorner with one DyS6 octahedra, corners with two equivalent CeS6 octahedra, corners with six DyS7 pentagonal bipyramids, edges with two equivalent DyS6 octahedra, edges with three equivalent CeS6 octahedra, and an edgeedge with one DyS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 2–58°. There are a spread of Dy–S bond distances ranging from 2.68–2.86 Å. Ce is bonded to six S atoms to form CeS6 octahedra that share corners with three DyS6 octahedra, corners with six DyS7 pentagonal bipyramids, edges with two equivalent CeS6 octahedra, edges with three equivalent DyS6 octahedra, and an edgeedge with one DyS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 2–58°. There are a spread of Ce–S bond distances ranging from 2.77–2.93 Å. There are seven inequivalent S sites. In the first S site, S is bonded to four Dy and one Ce atom to form SCeDy4 trigonal bipyramids that share corners with five SCeDy3 tetrahedra, corners with four SDy5 trigonal bipyramids, an edgeedge with one SDy4 tetrahedra, and edges with five SCeDy4 trigonal bipyramids. In the second S site, S is bonded to three Dy and two equivalent Ce atoms to form SCe2Dy3 trigonal bipyramids that share corners with five SCeDy3 tetrahedra, corners with four SDy5 trigonal bipyramids, an edgeedge with one SCeDy3 tetrahedra, and edges with five SCeDy4 trigonal bipyramids. In the third S site, S is bonded to five Dy atoms to form distorted SDy5 trigonal bipyramids that share corners with four equivalent SCeDy3 tetrahedra, corners with six SCeDy4 trigonal bipyramids, edges with three SCeDy3 tetrahedra, and edges with six SCe2Dy3 trigonal bipyramids. In the fourth S site, S is bonded to five Dy atoms to form distorted SDy5 trigonal bipyramids that share corners with four equivalent SDy4 tetrahedra, corners with six SCeDy4 trigonal bipyramids, edges with three SCeDy3 tetrahedra, and edges with six SCeDy4 trigonal bipyramids. In the fifth S site, S is bonded to three Dy and one Ce atom to form SCeDy3 tetrahedra that share corners with three SCeDy3 tetrahedra, corners with nine SCeDy4 trigonal bipyramids, and edges with four SCe2Dy3 trigonal bipyramids. In the sixth S site, S is bonded to four Dy atoms to form distorted SDy4 tetrahedra that share corners with three SCeDy3 tetrahedra, corners with nine SCeDy4 trigonal bipyramids, and edges with four SCeDy4 trigonal bipyramids. In the seventh S site, S is bonded in a rectangular see-saw-like geometry to two equivalent Dy and two equivalent Ce atoms.