Zur Thermochemie der seltenen Erden. I. Die Lösungswärmen der Metalle der seltenen Erden

Abstract

Es wird über die Herstellung und die Lösungswärmen der seltenen Erdmetalle berichtet. Gemessen wurden die Lösungswärmen von Scandium, Yttrium, Lanthan, Cer, Praseodym, Neodym, Gadolinium, Dysprosium, Holmium, Thulium und Cassiopeium (Tabelle 3, S. 367). Die Ergebnisse lassen auch hier die Sonderstellung des Gadoliniums mit halbbesetzter Schale im Sinne der Systematik von W. KLEMM deutlich erkennen.

The standard molar enthalpies of formation of the rare earth trihalides IV. DyCl3(s) and NdCl3(s)

“…(1)(2)(3) A systematic treatment of the available literature data for the enthalpies of formation D f H°m of the rare earth metal trihalides, recently undertaken in this laboratory, (4) indicated significant discrepancies in the existing experimental values for a number of the aforementioned compounds. For instance, in the case of DyCl 3 (s) and NdCl 3 (s), the title compounds of this work, the results of previous solution calorimetric studies (5)(6)(7)(8)(9)(10)(11)(12)(13) show a large scatter. The present investigation was undertaken to redetermine the standard molar enthalpies of formation of solid dysprosium trichloride and neodymium trichloride, and to clarify the thermochemistry of these compounds.…”

“…The value obtained by Bommer and Hohmann, (5) based on calorimetric measurements in 0.1 mol·dm − 3 HCl(aq), should be considered as tentative, due to the significant amount of impurities in especially the metal sample used as the reference material in their experiments. With the exception of Monaenkova et al, (13) all other authors measured the enthalpy of solution of the metal in 4.0 mol·dm − 3 HCl(aq).…”

“…auxiliary values. Again, the first value reported by Bommer and Hohmann (5) could be considered as a tentative value only, due to a poor quality and insufficient analytical characterization of the metal sample used. The concordant results by Spedding and Miller (6) and Polyachenok and Novikov (7) seem also to be not accurate due to contamination by non-metallic impurities in neodymium metal samples in these studies.…”

Thermochemical investigation of YBa2Cu3O7−δ superconductor doped by lutetium

“…We choose D sol H°( Lu) = À694.9 ± 1.0 kJ/mol [23] because the concentration is 2.19 which suites better to our conditions and because Lu is well-characterized in this paper [23]. There are four works [21,22,27,28] where solution enthalpy of Y was measured. In Ref.…”

“…28 Lu 2 O 3 were kept at 1023 K up to constant weight. CuO was heated in an O 2 atmosphere for 15 h (T = 900 K).…”