[en] The osmotic coefficients of the aqueous trichlorides of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y were determined from 0.1 M to saturation at 25⁰C. Semiempirical least-squares equations were obtained for the osmotic coefficients as a function of molality and these equations were used to calculate water activities and mean molal activity coefficients. The water activities of the light rare earth chlorides at constant molalities are higher than for the heavy rare earths, while the mean molal activity coefficients are larger for the heavy rare earths than for the light ones. The above effects are discussed in terms of changes in the cationic radii and hydration of the rare earth ions

[en] The heats of dilution of aqueous LaCl₃, PrCl₃, NdCl₃, SmCl₃, EuCl₃, GdCl₃, TbCl₃, DyCl₃, HoCl₃, ErCl₃, TmCl₃, YbCl₃, and LuCl₃ solutions have been measured up to saturation at 25⁰C. The integral heats of solution of LaCl₃ . 7H₂O, PrCl₃ . 7H₂O, NdCl₃ . 6H₂O, SmCl₃ . 6H₂O, EuCl₃ . 6H₂O, GdCl₃ . 6H₂O, TbCl₃ . 6H₂O, DyCl₃ . 6H₂O, HoCl₃ . 6H₂O, ErCl₃ . 6H₂O, TmCl₃ . 6H₂O, YbCl₃ . 6H₂O, and LuCl₃ . 6H₂O in water at 25⁰C have also been measured. The heat of dilution data are represented by empirical equations, and relative partial molal heat contents are calculated. The heat content trends across the rare earth chloride series are similar to the trends found for the rare earth perchlorate heat data, and can be correlated with a change in the inner sphere cation water coordination across the rare earth cation series. 11 figures, 3 tables, 43 references

[en] Depending on the thermochemical stability of gaseous species the gas adsorption chromatographic process can be a complex reaction. In this contribution thermochemical relationships are derived describing the dissociative, the associative and the substitutive adsorption. (author) 1 fig1 tab

[en] The author's phase and thermodynamic studies on the binary salt systems with common anion have shown that there is a quantitative relation between the phase diagram type and the ionic potentials of component cations of the system. The relation may be clearly presented using the binary uranium tetrachloride systems MCl_n-UCl₄ as an example. When all the systems whose phase diagrams are known are listed in sequence of decreasing values of the ionic potentials ratio of both component cations, a certain regularity may be observed: the phase diagram types change suddenly at some precise values of the ratio. Considering the thermodynamic characteristics of the liquid phases of some of the systems, we can observe that the dependence of the excess partial molar Gibbs energy of a component (and molar Gibbs energy of solution as well) on the cation potentials ratio, is linear within the limits of the group of systems of any definite type. (orig.)

[en] The preparation of rare earth trichlorides by reaction of rare earth oxides with aluminium trichloride and their purification by means of chemical vapour phase transport with aluminium trichloride is described. By the method used especially rare earth doted rare earth trichlorides are obtainable in one step. The method furthermore allows a simple preparation of europium trichloride, which is not easy to prepare in another way. Two modifications of terbium trichloride can be prepared depending on the exact temperature conditions of the chemical vapour phase transport. (author)

[en] Characteristics of the Voronoi-Dirichlet polyhedrons are estimated for 133 crystallographic cesium atoms in chlorides Cs_xM_yCl_z (M=Cd, Sc, V, Nb, Mo, W, Ru, Re, etc.). It is found that cesium atoms have coordination numbers 6,8,9,10, 11 and 12 as regards the chlorine atoms. The results of cesium atom coordination sphere examination by the crossing spheres method are presented. Metal-metal interactions (including Cs-Cs) in the structure of certain chlorides are revealed

[en] The reactions of the whole series of lanthanide trichlorides with graphite have been investigated. Intercalation compounds have been prepared with the chlorides of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y whereas LaCl₃, CeCl₃, PrCl₃ and NdCl₃ do not intercalate. The compounds were characterized by chemical and X-ray analysis. The amount of c-axis increase is consistent with the assumption that the chlorides are intercalated in form of a chloride layer sandwich resmbling the sheets in YCl₃. The chlorides which do not intercalate crystallize in the UCl₃ structure having 3 D arrangements of ions. Obviously, these chlorides cannot form sheets between the carbon layers. The ability of AlCl₃ to volatilize lanthanide chlorides through complex formation in the gas phase can be used to increase the intercalation rate strikingly. (author)

[en] The enthalpies of formation in a series of compounds of the type A₃MCl₆ resp. AM₂Cl₇ (A = K, Cs; M = Lanthanide(III) ion) were determined in an isoperibolic solution calorimeter. The enthalpies were used to calculate standard enthalpies of formation and lattice energies of the compounds. Both values were discussed in the relation to the structure of the compounds. (author)

[en] The electron paramagnetic resonance of trivalent gadolinium doped in the monoclinic single crystals of lanthanide trichloride hexahydrates (LnCl₃.6H₂0, where Ln³⁺ = Nd³⁺, Sm³⁺, Eu³⁺, Tb³⁺, Dy³⁺, Ho³⁺, Er³⁺, Tm³⁺, and Yb³⁺) has been observed at 9.4 GHz and at 297 K. From the observed spectra, which exhibit, on the whole, similar overall features in these homologous isostructural crystals, the spin-Hamiltonian parameter of Gd³⁺ have been computed. The magnitudes of the dominant second-order parameters b₂⁰ and b₂² increase progressively with decreasing ionic radii and decreasing unit cell volume of the host. The parameter b₂⁰ is found to be a linear function, whereas b₂² is a nonlinear function of the ionic radii. The experimental observations show that the overall zero-field splitting of Gd³⁺ in these crystals is clearly a linear function of the ionic radii of the trivalent host ions. The Gd³⁺ line widths are widely different in these hosts. (author)

[en] The transport of aqueous salts containing mono-, di- and trivalent metal and tetravalent metal complex ions across ultrathin polyvinylammonium/polyvinylsulphate (PVA/PVS) membranes is described. The membranes were prepared by electrostatic layer-by-layer (LBL) assembly of the two polyelectrolytes. Using spectroscopic measurements and permeability studies, it is demonstrated that the transport of copper(II) chloride, lanthanum(III) chloride, barium chloride and potassium hexacyanoferrate(II) is accompanied by the permanent incorporation of the metal and metal complex ions in the membrane. Upon the uptake of copper, lanthanum and hexacyanoferrate ions, the membranes become cross-linked so that the permeation rates of other salts not taken up by the membrane, e.g. sodium chloride, potassium chloride and magnesium chloride, are decreased. The uptake of barium ions leads to a decrease of the cross-linking density of the membrane so that the permeation rate of NaCl is increased. Possible mechanisms for the ion uptake are discussed