Monoclinic materials were obtained by reacting FeCl3 with AgCl. The Fe ions were found to be in a high-spin tetrahedral state. This compound was an inferior conductor, and this was attributed to the fact that the Ag+ ions were located in tetrahedral sites of the lattice; instead of being free to move in wide channels.

P.Palvadeau, J.P.Venien, M.Spiesser, J.Rouxel: Solid  State Ionics, 1982, 6[3], 231-6