“…Sublimation vapour pressures of FeCl 3 (cr) have been made using manometric [4][5][6][7], transpiration [6,9,10], Knudseneffusion [11,12], and spectrophotometric [13,14] techniques. Dynamic studies of FeCl 3 (cr) [6,10,11,15] and Fe 2 Cl 6 (g) [6,15,16] decomposition indicate that equilibration is slow. These studies, suggest that a direct study of the sublimation of FeCl 3 (cr) to the dimeric vapour should be possible using the Knudsen-effusion method without the complication of a concomitant chlorine partial pressure.…”