DOE OSTI2020
AgAlS2 is Ilmenite-like structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. Ag1+ is bonded in a 4-coordinate geometry to four S2- atoms. There are one shorter (2.45 Å) and three longer (2.73 Å) Ag–S bond lengths. Al3+ is bonded to six S2- atoms to form edge-sharing AlS6 octahedra. There are three shorter (2.39 Å) and three longer (2.48 Å) Al–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to one Ag1+ and three equivalent Al3+ atoms to form distorted SAl3Ag trigonal pyramids that share corners with six equivalent SAl3Ag3 octahedra, corners with six equivalent SAl3Ag trigonal pyramids, and edges with three equivalent SAl3Ag3 octahedra. The corner-sharing octahedra tilt angles range from 3–49°. In the second S2- site, S2- is bonded to three equivalent Ag1+ and three equivalent Al3+ atoms to form SAl3Ag3 octahedra that share corners with six equivalent SAl3Ag trigonal pyramids, edges with six equivalent SAl3Ag3 octahedra, and edges with three equivalent SAl3Ag trigonal pyramids.