DOE OSTI2020
Ag(Bi2S3)3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ag1+ is bonded to six S2- atoms to form AgS6 octahedra that share corners with two equivalent BiS6 octahedra, corners with four equivalent BiS5 square pyramids, edges with two equivalent AgS6 octahedra, and edges with six equivalent BiS5 square pyramids. The corner-sharing octahedral tilt angles are 55°. There are two shorter (2.51 Å) and four longer (2.98 Å) Ag–S bond lengths. There are three inequivalent Bi+2.83+ sites. In the first Bi+2.83+ site, Bi+2.83+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing BiS6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Bi–S bond distances ranging from 2.75–2.95 Å. In the second Bi+2.83+ site, Bi+2.83+ is bonded to six S2- atoms to form BiS6 octahedra that share a cornercorner with one AgS6 octahedra, corners with three BiS6 octahedra, corners with two equivalent BiS5 square pyramids, and edges with seven BiS6 octahedra. The corner-sharing octahedra tilt angles range from 0–55°. There are a spread of Bi–S bond distances ranging from 2.68–3.10 Å. In the third Bi+2.83+ site, Bi+2.83+ is bonded to five S2- atoms to form BiS5 square pyramids that share corners with two equivalent AgS6 octahedra, corners with two equivalent BiS6 octahedra, edges with three equivalent AgS6 octahedra, and edges with four equivalent BiS5 square pyramids. The corner-sharing octahedra tilt angles range from 13–64°. There are one shorter (2.61 Å) and four longer (2.85 Å) Bi–S bond lengths. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded to five Bi+2.83+ atoms to form SBi5 square pyramids that share corners with two equivalent SBi6 octahedra, corners with two equivalent SAgBi3 tetrahedra, edges with three equivalent SBi6 octahedra, and edges with four equivalent SBi5 square pyramids. The corner-sharing octahedral tilt angles are 4°. In the second S2- site, S2- is bonded to one Ag1+ and three Bi+2.83+ atoms to form distorted SAgBi3 tetrahedra that share a cornercorner with one SBi6 octahedra, corners with six SBi5 square pyramids, corners with three equivalent SAgBi3 tetrahedra, and edges with three equivalent SAg2Bi3 square pyramids. The corner-sharing octahedral tilt angles are 2°. In the third S2- site, S2- is bonded in a 3-coordinate geometry to three Bi+2.83+ atoms. In the fourth S2- site, S2- is bonded to two equivalent Ag1+ and three equivalent Bi+2.83+ atoms to form distorted SAg2Bi3 square pyramids that share corners with two equivalent SAg2Bi3 square pyramids, corners with four equivalent SAgBi3 tetrahedra, edges with five equivalent SAg2Bi3 square pyramids, and edges with three equivalent SAgBi3 tetrahedra. In the fifth S2- site, S2- is bonded to six Bi+2.83+ atoms to form SBi6 octahedra that share corners with four equivalent SBi5 square pyramids, corners with two equivalent SAgBi3 tetrahedra, edges with two equivalent SBi6 octahedra, and edges with six equivalent SBi5 square pyramids.