DOE OSTI2020
K3Ta2Ag3S8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of K–S bond distances ranging from 3.24–3.57 Å. In the second K1+ site, K1+ is bonded in a body-centered cubic geometry to eight S2- atoms. There are a spread of K–S bond distances ranging from 3.52–3.64 Å. Ta5+ is bonded to four S2- atoms to form TaS4 tetrahedra that share edges with three AgS4 tetrahedra. There are a spread of Ta–S bond distances ranging from 2.29–2.33 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded to four S2- atoms to form AgS4 tetrahedra that share corners with four equivalent AgS4 tetrahedra and edges with two equivalent TaS4 tetrahedra. There are two shorter (2.57 Å) and two longer (2.58 Å) Ag–S bond lengths. In the second Ag1+ site, Ag1+ is bonded to four S2- atoms to form AgS4 tetrahedra that share corners with two equivalent AgS4 tetrahedra and edges with two equivalent TaS4 tetrahedra. There are a spread of Ag–S bond distances ranging from 2.55–2.60 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Ta5+, and two Ag1+ atoms. In the second S2- site, S2- is bonded in a 6-coordinate geometry to four K1+, one Ta5+, and one Ag1+ atom. In the third S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Ta5+, and one Ag1+ atom. In the fourth S2- site, S2- is bonded in a 1-coordinate geometry to two K1+, one Ta5+, and two Ag1+ atoms.