DOE OSTI2020
Sr(YbS2)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 2.96–3.20 Å. There are two inequivalent Yb3+ sites. In the first Yb3+ site, Yb3+ is bonded to six S2- atoms to form YbS6 octahedra that share corners with four equivalent YbS5 square pyramids and edges with four equivalent YbS6 octahedra. There are a spread of Yb–S bond distances ranging from 2.70–3.01 Å. In the second Yb3+ site, Yb3+ is bonded to five S2- atoms to form distorted YbS5 square pyramids that share corners with four equivalent YbS6 octahedra and edges with two equivalent YbS5 square pyramids. The corner-sharing octahedra tilt angles range from 53–70°. There are a spread of Yb–S bond distances ranging from 2.63–3.04 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to two equivalent Sr2+ and three Yb3+ atoms to form distorted edge-sharing SSr2Yb3 square pyramids. In the second S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Sr2+, two equivalent Yb3+, and one S2- atom. The S–S bond length is 2.14 Å. In the third S2- site, S2- is bonded to two equivalent Sr2+ and three Yb3+ atoms to form a mixture of distorted edge and corner-sharing SSr2Yb3 trigonal bipyramids. In the fourth S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent Sr2+, three equivalent Yb3+, and one S2- atom.