Gaseous Complexes of Gadolinium Chloride with Aluminum and Iron Chlorides

Abstract

REACTION OF HYDROGEN WITH URANIUM 1601the hydride and during dehydriding may be responsible for tl~e apparent slow decomposition rate described above. ConclusionThe hyriding of uranium powder was found to follow a two-thirds order rate in 13.3 kPa of hydrogen but increased to a first-order rate as the hydrogen pressure was increased to 26.6 kPa. Comparison of the phase boundary with the progressive conversion reaction models showed little difference between the two. The progressive conversion model did fit all of the data from 0 to 100% reaction. Increasing the temperature reduced the hydriding rate, which can be predicted using a model with adsorption as the rate-controlling step. This resulted in an apparent negative activation energy of --1.59 kcal/mole. Repeated hydriding/dehydriding cycles increased the surface area of the sample and also the reaction rate for the first five cycIes. Subsequent cycling had little effect on the surface area. Dehydriding was found to be zero order with an activation energy of 9.5 kcal/mole over the temperature range 200~176 ABSTRACT In view of a possible application for the chemical vapor deposition of Gd~Fe5012 the equilibria GdCl~(s) ~-1.5LfCle(g) ----GdI4Cll~(g), L = A.I, Fe

Formation thermodynamics of the rare earth vapour complexes: DyAl3Cl12and DyAl2Cl9

“…(11)(12)(13)(14)(15)(16) This method was first reported by Papatheodorou and Kucera (13) for preparing SmCl 3 , and chlorides and bromides of other lanthanides and actinides, and then used by Steidl et al (15,16) for preparing GdCl 3 , TmCl 3 , and YbCl 3 .…”

“…The ampoules were similar to those described in the literature. (14,30) An excess of DyCl 3 and less AlCl 3 were placed in the well at part A of the ampoule (see figure 1). After having been purged with pure argon gas and evacuated several times and sealed, four ampoules were placed in a graphite container and then put into a furnace where the temperature was kept constant 20.5 K, measured with a {platinum-to-(platinum + 10 mass per cent of ruthenium 10)} thermocouple, to ensure that the four samples were at the same temperature.…”

“…(11)(12)(13)(14)(15)(16)29) The gaseous aluminium chloride reacted with only part of the DyCl 3 (s) so that the activity of DyCl 3 (s) in the well at part A of the ampoule was always equal to unity at the equilibrating temperature. The equilibria (2) and (3) were attained within 6 h. After the equilibrium was attained, part B of the ampoule (see figure 1) was covered with asbestos and quickly quenched with water.…”

“…Formation thermodynamics of the rare earth vapour complexes LnAl n Cl 3n + 3 have been investigated for Ln = Nd with n = 1, (11) 3, (12) and 4, (12) for Ln = Sm with n = 3, (13) for Ln = Gd with n = 3, (14) and for Ln = Gd, (15) Tm, (15) and Yb (16) with n = 1 to 4. The methods used to investigate these systems are mass spectrometric analysis, (11) u.v.-vis spectrometric analysis, (12,13) entrainment, quenching and chemical transport experiments, (14) and radiochemical analysis.…”

“…The methods used to investigate these systems are mass spectrometric analysis, (11) u.v.-vis spectrometric analysis, (12,13) entrainment, quenching and chemical transport experiments, (14) and radiochemical analysis. (15,16) We have reported thermodynamic measurements for aqueous solutions (17,18) and non-aqueous solutions (19) at room temperature, and for molten alloys, (20)(21)(22)(23) molten salt mixtures, (24,25) and molten slags (26)(27)(28) at high temperature.…”