DOE OSTI2020
AgGdS2 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are four inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded to six S2- atoms to form GdS6 octahedra that share corners with four equivalent GdS6 octahedra, corners with three AgS5 trigonal bipyramids, edges with four GdS6 octahedra, and edges with six AgS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 18–23°. There are a spread of Gd–S bond distances ranging from 2.76–2.80 Å. In the second Gd3+ site, Gd3+ is bonded to six S2- atoms to form GdS6 octahedra that share corners with four equivalent GdS6 octahedra, corners with three AgS5 trigonal bipyramids, edges with four GdS6 octahedra, and edges with six AgS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 18–23°. There are a spread of Gd–S bond distances ranging from 2.75–2.81 Å. In the third Gd3+ site, Gd3+ is bonded to six S2- atoms to form GdS6 octahedra that share corners with four equivalent GdS6 octahedra, corners with three AgS5 trigonal bipyramids, edges with four GdS6 octahedra, and edges with six AgS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 18–23°. There are a spread of Gd–S bond distances ranging from 2.76–2.81 Å. In the fourth Gd3+ site, Gd3+ is bonded to six S2- atoms to form GdS6 octahedra that share corners with four equivalent GdS6 octahedra, corners with three AgS5 trigonal bipyramids, edges with four GdS6 octahedra, and edges with six AgS5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 19–22°. There are a spread of Gd–S bond distances ranging from 2.76–2.80 Å. There are four inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded to five S2- atoms to form distorted AgS5 trigonal bipyramids that share corners with three GdS6 octahedra, corners with six AgS5 trigonal bipyramids, edges with six GdS6 octahedra, and an edgeedge with one AgS5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 11–79°. There are a spread of Ag–S bond distances ranging from 2.46–3.19 Å. In the second Ag1+ site, Ag1+ is bonded to five S2- atoms to form distorted AgS5 trigonal bipyramids that share corners with three GdS6 octahedra, corners with six AgS5 trigonal bipyramids, edges with six GdS6 octahedra, and an edgeedge with one AgS5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 12–75°. There are a spread of Ag–S bond distances ranging from 2.47–3.21 Å. In the third Ag1+ site, Ag1+ is bonded to five S2- atoms to form distorted AgS5 trigonal bipyramids that share corners with three GdS6 octahedra, corners with six AgS5 trigonal bipyramids, edges with six GdS6 octahedra, and an edgeedge with one AgS5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 10–80°. There are a spread of Ag–S bond distances ranging from 2.45–3.26 Å. In the fourth Ag1+ site, Ag1+ is bonded to five S2- atoms to form distorted AgS5 trigonal bipyramids that share corners with three GdS6 octahedra, corners with six AgS5 trigonal bipyramids, edges with six GdS6 octahedra, and an edgeedge with one AgS5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 10–81°. There are a spread of Ag–S bond distances ranging from 2.45–3.29 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded in a 6-coordinate geometry to three Gd3+ and three Ag1+ atoms. In the second S2- site, S2- is bonded to three Gd3+ and two equivalent Ag1+ atoms to form a mixture of distorted edge and corner-sharing SGd3Ag2 square pyramids. In the third S2- site, S2- is bonded to three Gd3+ and two Ag1+ atoms to form a mixture of distorted edge and corner-sharing SGd3Ag2 square pyramids. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to three Gd3+ and three Ag1+ atoms. In the fifth S2- site, S2- is bonded to three Gd3+ and two Ag1+ atoms to form a mixture of distorted edge and corner-sharing SGd3Ag2 square pyramids. In the sixth S2- site, S2- is bonded in a 6-coordinate geometry to three Gd3+ and three Ag1+ atoms. In the seventh S2- site, S2- is bonded to three Gd3+ and two equivalent Ag1+ atoms to form a mixture of distorted edge and corner-sharing SGd3Ag2 square pyramids. In the eighth S2- site, S2- is bonded in a 6-coordinate geometry to three Gd3+ and three Ag1+ atoms.