Journal of Chemical and Engineering Data, Vol.41, No.1, 14-20, 1996
Vapor-Pressure and Standard Enthalpies of Sublimation of Iron Difluoride, Iron Dichloride, and Iron Dibromide
Vapor pressures of solid FeF2, FeCl2, and FeBr2, were measured by the torsion and Knudsen methods and the following equations, valid in the reported temperature ranges, were derived : log{p(FeF2)/kPa} = 10.58 +/- 0.20 - (13740 +/- 200)(K/T) (958-1178 K), log{p(FeCl2)/kPa} = 10.95 +/- 0.30 - (10390 +/- 300)-(K/T) (693-866 K), and log{p(FeBr2)/kPa} = 11.09 +/- 0.20 - (10320 +/- 250)(WT) (655-833 K). The following standard sublimation enthalpies were determined by second- and third-law treatment of the vapor pressures : Delta(sub)H degrees(298 K) = 271 +/- 2, 204 +/- 4, and 208 +/- 2 kJ . mol(-1) for iron difluoride, dichloride, and dibromide, respectively.