Vaporization of DyBr3(s) and thermochemistry of the dimer homocomplex (DyBr3)2(g)

Abstract

Thermochemistry of the molecule (ZnI2)2(g) and the vaporization of ZnI2(s)The vaporization of DyBr 3 ͑s͒ was investigated in the temperature range between 803 and 1053 K by Knudsen effusion mass spectrometry. The ions Dy ϩ , DyBr ϩ , DyBr 2 ϩ , DyBr 3 ϩ , Dy 2 Br 5 ϩ , and Br ϩ were detected and their appearance potentials determined leading to an upper bound for the atomization energy of DyBr 3 ͑g͒. The species DyBr 3 ͑g͒ and ͑DyBr 3 ͒ 2 ͑g͒ were identified in the vapor and their partial pressures determined using quantitative vaporization. Enthalpies and entropies of sublimation resulted according to the second-law and third-law methods. The enthalpy and entropy changes of the dissociation reaction ͑DyBr 3 ͒ 2 ͑g͒ ϭ 2 DyBr 3 ͑g͒ were obtained as ⌬ d H 298 0 ϭ220.8Ϯ6.6 kJ mol Ϫ1 and ⌬ d S 298 0 ϭ163.7Ϯ8.5 J mol Ϫ1 K Ϫ1 .

Quantum Chemical Studies of Neutral and Ionized DyX, DyX2, and DyX3 Species (X = F, Cl, Br, I) and the Implications for the Mass Spectra of Gaseous DyX3

“…The energy of the ionising electrons, 34 eV, was calibrated with the ionization potentials of Hg, In, and Ag measured prior to the recording of the DyF 3 mass spectra. Mass spectra and appearance potentials for ions present in the mass spectra of DyCl 3 ,7,8 DyBr 3 ,9 and DyI 3 10 were taken from our previous studies. The mass spectrum of DyCl 3 8 and the appearance potentials for ions in the DyI 3 mass spectrum24 were also taken from the literature.…”

“…Brunetti et al6 and Kapala et al7 have published a comparison of thermodynamic data reported in the literature. Recently, the vaporization thermodynamics of DyCl 3 ,7,8 DyBr 3 ,9 and DyI 3 10 were investigated by means of Knudsen effusion mass spectrometry using different equipment and experimental conditions. The ion‐molecule reactions in the DyCl 3 vapors were studied as well 8.…”

Vaporization Studies of Dysprosium Trichloride, Tribromide, and Triiodide

“…As concerns DyBr 3 , apparently not many studies on the vaporization of this compound were found in the literature. In particular, the only vapor pressure values were those measured at high temperatures (1220-1535 K) by boiling points (Makhmadmurodov et al, 1975;Makhmadmurodov et al, 1989) and at lower temperatures (873-1053 K), over the solid phase, by a mass spectrometer (Hilpert et al, 1995). The derived standard enthalpies, ∆ sub H°(298 K) ) 273 ( 14 kJ mol -1 (second-law, Makhmadmurodov et al, 1975) and 278.4 ( 7.4 and 283.9 ( 11.3 kJ mol -1 (secondand third-law, respectively, Hilpert et al, 1995) are in agreement within their errors.…”

“…In particular, the only vapor pressure values were those measured at high temperatures (1220-1535 K) by boiling points (Makhmadmurodov et al, 1975;Makhmadmurodov et al, 1989) and at lower temperatures (873-1053 K), over the solid phase, by a mass spectrometer (Hilpert et al, 1995). The derived standard enthalpies, ∆ sub H°(298 K) ) 273 ( 14 kJ mol -1 (second-law, Makhmadmurodov et al, 1975) and 278.4 ( 7.4 and 283.9 ( 11.3 kJ mol -1 (secondand third-law, respectively, Hilpert et al, 1995) are in agreement within their errors. In addition to the monomer, also the presence of a small amount of the dimer form was observed by Hilpert et al (1995) so that the dissociation process of the dimer was also studied by these authors.…”

Chemistry, commentary and community: Discussion of “The NaDyBr4 complex: its molecular structure and thermodynamic properties” by Varga and Hargittai

“…This means that only 58 kJ/mol, some 20%, of the bond energy of NaBr remains upon loss of 1 We could have considered the reaction of NaBr with the ion DyBr 3 + and its corresponding dissociation energy. However, since the ionization potential of DyBr 3 [2,6] is higher than that of NaBr, we are ignoring this process for now in favor of the thermodynamically preferred reaction pathway, whether or not it is more kinetically favored. an electron, as befits the description of this diatomic as Na + Br − .…”