Zum thermochemischen Verhalten von Halogeniden,Oxidhalogeniden, Aluminiumhalogeniden und Ammoniumhalogeniden der Seltenerdelemente

The Thermochemical Behaviour of Halides, Oxidehalides, Aluminiumhalides and Ammoniumhalides of Rare‐Earth‐Elements After a critical sifting of the thermal behaviour of Rare earth halides LnX₃, oxide halides LnOX, aluminium halides Ln_mAl_nX_3(m+n) and ammonium halides (NH₄)_xLn_yX_3y+x the enthalpies of formation and the standard entropies are evaluated and the recommended values are indicated. From the straight‐line dependence between the differences of the enthalpies of formation of Rare earth oxides and ‐halides as well as ‐oxidhalides and the ion radii of the concerned elements the values for some halides and oxide halides, which are missing in the literature, are deduced. The evaporation and sublimation behaviour of the LnX₃ as well as the decomposition behaviour of the compounds LnOX are generalizing described and chemical vapour transport properties of the LnX₃ with AlX₃ are systematically arranged. The thermal stability of the Europium trihalides is quantified. From the well known phase barograms and diagrams of the systems Rare earth trihalide/aluminium halide (LnX₃/AlX₃) and ammonium halide (LnX₃/NH₄X) general conclusions are deduced for systems with LnX₃.