ErAgS2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. Er(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form ErS6 octahedra that share corners with six equivalent Er(1)S6 octahedra, edges with four equivalent Er(1)S6 octahedra, and edges with eight equivalent Ag(1)S6 octahedra. The corner-sharing octahedra are not tilted. Ag(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form AgS6 octahedra that share corners with six equivalent Ag(1)S6 octahedra, edges with four equivalent Ag(1)S6 octahedra, and edges with eight equivalent Er(1)S6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent S sites. In the first S site, S(1) is bonded to four equivalent Er(1) and two equivalent Ag(1) atoms to form SEr4Ag2 octahedra that share corners with six equivalent S(1)Er4Ag2 octahedra, edges with four equivalent S(1)Er4Ag2 octahedra, and edges with eight equivalent S(2)Er2Ag4 octahedra. The corner-sharing octahedra are not tilted. In the second S site, S(2) is bonded to two equivalent Er(1) and four equivalent Ag(1) atoms to form SEr2Ag4 octahedra that share corners with six equivalent S(2)Er2Ag4 octahedra, edges with four equivalent S(2)Er2Ag4 octahedra, and edges with eight equivalent S(1)Er4Ag2 octahedra. The corner-sharing octahedra are not tilted.
ErAgS2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. Er(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form ErS6 octahedra that share corners with six equivalent Er(1)S6 octahedra, edges with four equivalent Er(1)S6 octahedra, and edges with eight equivalent Ag(1)S6 octahedra. The corner-sharing octahedra are not tilted. Both Er(1)-S(2) bond lengths are 2.71 Å. All Er(1)-S(1) bond lengths are 2.77 Å. Ag(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form AgS6 octahedra that share corners with six equivalent Ag(1)S6 octahedra, edges with four equivalent Ag(1)S6 octahedra, and edges with eight equivalent Er(1)S6 octahedra. The corner-sharing octahedra are not tilted. Both Ag(1)-S(1) bond lengths are 2.71 Å. All Ag(1)-S(2) bond lengths are 2.77 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to four equivalent Er(1) and two equivalent Ag(1) atoms to form SEr4Ag2 octahedra that share corners with six equivalent S(1)Er4Ag2 octahedra, edges with four equivalent S(1)Er4Ag2 octahedra, and edges with eight equivalent S(2)Er2Ag4 octahedra. The corner-sharing octahedra are not tilted. In the second S site, S(2) is bonded to two equivalent Er(1) and four equivalent Ag(1) atoms to form SEr2Ag4 octahedra that share corners with six equivalent S(2)Er2Ag4 octahedra, edges with four equivalent S(2)Er2Ag4 octahedra, and edges with eight equivalent S(1)Er4Ag2 octahedra. The corner-sharing octahedra are not tilted.