DOE OSTI2020
Nd(ErS2)3 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to seven S2- atoms to form distorted ErS7 pentagonal bipyramids that share corners with three ErS6 octahedra, edges with two equivalent ErS6 octahedra, and edges with four equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 38–51°. There are a spread of Er–S bond distances ranging from 2.68–2.91 Å. In the second Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, a cornercorner with one ErS7 pentagonal bipyramid, edges with four equivalent ErS6 octahedra, and edges with two equivalent ErS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 57–61°. There are a spread of Er–S bond distances ranging from 2.66–2.76 Å. In the third Er3+ site, Er3+ is bonded to six S2- atoms to form ErS6 octahedra that share corners with three equivalent ErS6 octahedra, corners with two equivalent ErS7 pentagonal bipyramids, and edges with four equivalent ErS6 octahedra. The corner-sharing octahedra tilt angles range from 57–61°. There are a spread of Er–S bond distances ranging from 2.64–2.77 Å. Nd3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Nd–S bond distances ranging from 2.89–3.03 Å. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to four Er3+ atoms. In the second S2- site, S2- is bonded to three Er3+ and one Nd3+ atom to form distorted SNdEr3 trigonal pyramids that share corners with two equivalent SNd2Er3 square pyramids, corners with four SNd2Er3 trigonal bipyramids, corners with four SNdEr3 trigonal pyramids, edges with three equivalent SNd2Er3 square pyramids, and edges with two equivalent SNd3Er2 trigonal bipyramids. In the third S2- site, S2- is bonded to four Er3+ atoms to form distorted SEr4 trigonal pyramids that share corners with three equivalent SNd2Er3 square pyramids, corners with four equivalent SNd2Er3 trigonal bipyramids, corners with four SNdEr3 trigonal pyramids, an edgeedge with one SNd2Er3 trigonal bipyramid, and edges with two equivalent SEr4 trigonal pyramids. In the fourth S2- site, S2- is bonded to three equivalent Er3+ and two equivalent Nd3+ atoms to form distorted SNd2Er3 square pyramids that share corners with six SNd2Er3 trigonal bipyramids, corners with five SNdEr3 trigonal pyramids, edges with four equivalent SNd2Er3 square pyramids, edges with two SNd2Er3 trigonal bipyramids, and edges with three equivalent SNdEr3 trigonal pyramids. In the fifth S2- site, S2- is bonded to three Er3+ and two equivalent Nd3+ atoms to form distorted SNd2Er3 trigonal bipyramids that share corners with two equivalent SNd2Er3 square pyramids, corners with two equivalent SNd3Er2 trigonal bipyramids, corners with seven SNdEr3 trigonal pyramids, an edgeedge with one SNd2Er3 square pyramid, edges with five SNd2Er3 trigonal bipyramids, and an edgeedge with one SEr4 trigonal pyramid. In the sixth S2- site, S2- is bonded to two equivalent Er3+ and three equivalent Nd3+ atoms to form distorted SNd3Er2 trigonal bipyramids that share corners with four equivalent SNd2Er3 square pyramids, corners with two equivalent SNd2Er3 trigonal bipyramids, a cornercorner with one SNdEr3 trigonal pyramid, an edgeedge with one SNd2Er3 square pyramid, edges with seven SNd2Er3 trigonal bipyramids, and edges with two equivalent SNdEr3 trigonal pyramids.