No abstract available

No abstract available

[en] The positive ions produced by electron impact on CeI₃ have been studied with a mass spectrometer having a heatable collision chamber with an attached, separately heatable sample reservoir. The individual ion appearance curves have been measured with a resolution of 0.15 eV, using the retarding potential difference technique. The ion appearance potentials have been determined from the appearance curves by a linear extrapolation technique which accounts for the curvature in the immediate vicinity of the threshold. The appearance potentials give estimates of the heats of formation of the various ions and of the ionization potentials of the corresponding fragments of CeI₃. The resulting recommended values are ΔH/sub f/(CeI⁺₃) =128 kcal/mole (5.53 eV), I.P.(CeI₃) =9.05 eV; ΔH/sub f/(CeI⁺₂) =113 kcal/mole (4.92 eV), I.P.(CeI₂) =6.75 eV; ΔH/sub f/(CeI⁺) =171 kcal/mole (7.41 eV); I.P.(CeI) =5.9 eV; ΔH/sub f/(Ce⁺) =228 kcal/mole (9.90 eV), I.P.(Ce) =5.65 eV

[en] An apparatus is described which permits heating of solid samples to temperatures up to approx.1000 degreeK, and confinement of the resulting vapor in a collision chamber held at a suitably higher temperature. The collision chamber is traversed by an electron beam and the resulting ions are identified by mass analysis. Measurements are reported of the negative ions produced by electron impact on CeI₃ molecules in the vapor phase. Fragment ions I^-, I^-₂, CeI^-, and CeI^-₂ are observed, and their appearance potentials are interpreted in the light of available knowledge of bond strengths (D) and affinities (A). Resulting derived quantities include D (CeI₂--I) < or =3.0 eV; A (CeI₂) > or =0.3 eV; D (CeI--I₂) < or =5.7 eV; D (Ce--I) > or =3.8 eV, and D (Ce--2I) > or =8.0 eV. CeI^-₃ is also observed, formed by direct attachment of very low energy electrons, and additionally by the charge transfer reaction CeI^-₂+CeI₃→CeI^-₃+CeI₂, suggesting that the affinity of CeI₃ exceeds that of CeI₂. In addition to the ions formed by electron impact, measurements of the background ion signals of I^- and CeI^-₄ are reported and interpreted to give the heat of formation of gaseous CeI^-₄, ΔH/sub f//sub ,/₂₉₈[CeI^-₄(g)]=-193 kcal/mole

No abstract available

[en] The phase equilibria in the cerium(III) iodide–cesium iodide pseudobinary system were established by differential scanning calorimetry. The system is characterized by existence of three compounds: Cs₃CeI₆, Cs₃Ce₂I₉ and CsCe₂I₇. First one, namely Cs₃CeI₆, melts congruently at 823 K and undergoes two phase transitions at 658 and 762 K. Second compound, Cs₃CeI₆, decomposes in the solid state at 610 K. The last existing compound, CsCe₂I₇, melts incongruently at 826 K. The eutectics composition was found from Tammann plot, which predicts, through application of the lever rule, the variation of the enthalpy associated with eutectic melting as a function of composition. The composition of CsI–Cs₃CeI₆ and Cs₃CeI₆–CsCe₂I₇ eutectics corresponds to cerium(III) iodide mole fraction x = 0.127 (T = 823 K) and x = 0.485 (T = 737 K), respectively.

[en] The dependence of the injection current on the sign of non-compensated electric charge of electret has been studied. Volt-ampere curves of the cathode currents through thin dielectric films of terylene and fluoroplastic have been considered. In ection currents have been observed in redox systems of Ce⁴⁺/Ce³⁺, I⁰/I^-, films serving as cathodes. From the anodic side the solution contained 1M KCl. An effect of the electret state of the film on a limiting injection current has been observed, when adsorption is accompanied by a charge transfer of one of the reagents

[en] Phase equilibria in the systems GdI₃-CeI₃-H₂O and GdI₃x5CO(NH₂)₂-H₂O are studied at 0 deg C using the isothermal method. In both cases formation of solid solutions of the I type according to the Rosebom classification is established. Using the data on solubility and the theory of regular solutions over the whole concentration range complete enthalpies of solid solution formations in each system are calculated

No abstract available

[en] Phase equilibria in the DyI₃-HI-H₂O and CeI₃-DyI₃-H₂O systems have been stUdied by the isothermal solubility method at 0 deg C. In the CeI₃-DyI₃H₂O system a continuous series of solid solutions has been found. The dependence of the total enthalpy of forming solid solutions on their composition has been determined