The vapor pressure of americium(III) chloride: An ultramicro apparatus for the determination of saturation vapor pressures of actinide halides

Abstract

The saturation vapor pressure of americium(III) chloride was determined by means of a floating cup apparatus based on the same principle as the earlier apparatus of W. Fischer and employing 100 – 200 μg of material. From seven independent runs, the following vapor pressure equation for AmCl 3 was derived. log(p, in mm Hg) = − (11826 ± 1132) T + (10.7 ± 1.2) where 1098 K< T<1343 K. From this equation, the following thermodynamic parameters were calculated: ΔH v = 208.5 kJ rmmol −1, ΔH° (298) = 341.5 kJ mol −1, ΔH(0) = 297.9 kJ mol −1, ΔS v = 136.6 J mol −1 K −1, ΔS° (298) = 293.8 J mol −1 K −1, gDG v (1000) = 77.8 kJ mol −1. The extrapolated boiling point was found to be 1526 K (= 1253 °C).