title: Solubility of rare earth metal bromides and iodides in aqueous systems.
abstract: The International Union of Pure and Applied Chemistry (IUPAC) project of collection, compilation, and critical evaluation of solubility data of bromides and iodides of the scandium group and all lanthanides in water and aqueous systems containing either halide acids, halide salts, or organic compounds is under preparation. As a result of their similarity to the chlorides, which were recently evaluated, the bromides and iodides in the lanthanide series should show some regularities in their solubility data. Unfortunately, the corresponding results show a large scatter when ordered according to the atomic number. Thus, it is complicated to select the best data for recommendation. Reasons for the inaccuracy of solubility measurements are outlined. In fact some solubility values of bromides predicted by correlation with chlorides seem to be more reliable than the experimental ones. As sufficient experimental data at various temperatures were available, the water-rich fragment of the LaBr3-H2O equilibrium phase diagram has been formed and depicted. It seems to be similar to the well-known LaCl3-H2O diagram. Several regularities, with respect to stoichiometry and solubility of compounds formed, were observed during investigations of the aqueous ternary systems. The complex iodides of various lanthanides display more regularities in their properties than the bromides do.
authors.affiliation: Department of Chemistry, University of Warsaw, Pasteura 1, 02093 Warsaw, Poland.
authors.forename: Cezary
authors.initials: C
authors.lastname: Gumiński
authors.affiliation: Institut f. Anorganische Chemie, TU Bergakademie Freiberg, Leipziger Str. 29, Freiberg, 09596 Germany.
authors.forename: Heidelore
authors.initials: H
authors.lastname: Voigt
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083 People's Republic of China.
authors.forename: Dewen
authors.initials: D
authors.lastname: Zeng
keywords: Hydrates; Phase diagrams; Rare earth metal bromides; Rare earth metal iodides; Solubility; Thermochemistry