Dampfdruckmessungen an Halogeniden der Seltenen Erden

Abstract

Inhaltsiibcrsicht Die Sublimationsdrucke der Halogenide von Lanthan, Cer, Praseodym und Neodym (ausschlieBlich der Fluoride und von Cerjodid) wurden nach der KNuDsENschen Effusionsmethode gemessen, aus den MeBergebnissen wurden die Sublimationswarme und andere thermodynamische Werte der Salze berechnet. Wenn der Radius des Kations abnimmt odcr der des Anions zunimmt, also beini ijbergang vom Lanthanchlorid zum Keodymchlorid oder vom Lanthanchlorid zum Lanthanjodid, sinkt die Sublimationswarme; dies wird als Folge der Deformation der Ionen angesehen.

Mass spectrometric investigation of neutral and charged constituents in saturated vapor over PrI3

“…3, the data from different authors agree well except for Ref. [8]. The total pressure of PrI 3 determined in Ref.…”

“…Nevertheless, the second low average value s H • (298.15 K) = 291 kJ mol −1 coincides with the third law average value (the value of Ref. [8] was not considered, see above) and it is accepted as the recommended one. The sublimation enthalpy in the form of dimer molecules was determined for the first time.…”

“…The total pressure of PrI 3 determined in Ref. [8] is about three times lower. The probable reason for that is a chemical interaction (3) a Atoms in bridge and terminal position are shown by b and t indexes, respectively.…”

“…No evidence for the presence of dimer molecules in the vapor was found by Knudsen mass spectrometry by Hirayama and Castle [11]. Therefore the processing of experimental data [8][9][10] was carried out on the assumption of a monomer composition of saturated vapor.…”

“…The saturated vapor pressure over PrI 3 was previously measured by the Knudsen effusion method (Shimazaki and Niwa [8]; Hirayama and Camp [9]) and the torsion method (Villani et al [10]). No evidence for the presence of dimer molecules in the vapor was found by Knudsen mass spectrometry by Hirayama and Castle [11].…”