Thermodynamic Properties of the Melt of the NaI — DyI<sub>3</sub> System

Hilpert, K.; Miller, M.; Gerads, H.; Saha, Biswajit

doi:10.1002/bbpc.19900940108

Cited by 9 publications

(1 citation statement)

References 14 publications

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“…The Cs 2 I 2 dimer signals are absent, while the CsI signal is significantly lower than in case of the alkali rich mixture with composition 5:2. The composition dependence of the amount of the MDyX 4 vapor complex has previously been investigated by mass spectroscopy for NaI–DyI 3 mixtures, with results matching the present findings …”

Section: Resultssupporting

confidence: 87%

Molecular Structure and Vibrational Spectra of Mixed MDyX₄ (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study

et al. 2011

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The structures, energetic, and vibrational properties of MDyX(4) (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) mixed alkali halide/dysprosium halide complexes have been investigated by a joint computational and experimental, matrix-isolation Fourier-transform infrared spectroscopic (MI-IR), study. According to our DFT computations for the complexes with heavier halides and alkali metals the ground-state structure is the tridentate isomer; while at high temperatures the bidentate structural isomer dominates. The survey of various dissociation processes revealed the preference of the dissociation to neutral MX and DyX(3) fragments over ionic and radical dissociation products. Cationic complexes are considerably less stable at 1000 K than the neutral complexes, and they prefer to dissociate to M(+) + DyX(4)(•) fragments. The vapor species of selected mixtures of NaBr and CsBr with DyBr(3) and of CsI with DyI(3) in the temperature range 900-1000 K have been isolated in krypton and xenon matrices and investigated by infrared spectroscopy. Besides the characteristic vibrational frequencies of the monomeric and dimeric alkali halide species and of the dysprosium trihalide molecules, certain signals indicated the formation of MDyX(4) (M = Na, Cs; X = Br, I) mixed complexes. Comparison with the computed vibrational and thermodynamic characteristics of the relevant species lead to the conclusion that these complexes appear in the vapor predominantly as the C(2v)-symmetry bidentate isomer. This is the first time that this structure was identified in an experimental vibrational spectroscopic study. The signals appearing upon performing a thermal anneal cycle were tentatively assigned to the double complex M(2)DyX(5) (M = Na, Cs; X = Br, I). A structure in which one alkali atom is bound to dysprosium by three and the other by two bridges is proposed for these double complexes.

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Section: Resultssupporting

confidence: 87%

Molecular Structure and Vibrational Spectra of Mixed MDyX₄ (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study

et al. 2011

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High temperature mass spectrometry in materials research

Hilpert¹

1991

Rapid Comm Mass Spectrometry

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Vaporization is an important property in materials research since it limits the use of the materials at high temperatures and since valuable thermodynamic data can be determined from vapour pressures. High-temperature mass spectrometry is the most versatile method for the elucidation of vaporization processes. Numerous results have been obtained. This article describes the fundamentals of the method and gives examples of its application. These examples describe the determination of thermodynamic properties for the gaseous species and condensed phases. The materials considered are salts, alloys and graphitic materials. They are of interest for metal halide lamps, superalloys, and nuclear reactors.All materials vaporize if the temperature is sufficiently high. The vaporization of materials generally limits their use. Ceramic materials, for example, often decompose at high temperatures by incongruent vaporization. On the other hand, thermodynamic data of the condensed phase can be obtained from the partial pressures of the evaporating species. The vapour pressure methods are standard for the determination of thermodynamic properties in addition to calorimetry and the galvanic cell methods. It follows from the aforementioned that vaporization is an important property in materials research.High-temperature mass spectrometry is the most important method for the analysis of vapours over condensed phases. The first investigation in this field was carried out in 1948 by Ionov.' He showed that the equilibrium vapour over the alkali halides MX(s) essentially consists of the monomer and dimer molecules MX(g) and (MX),(g). In 1953 Chupka and Inghram' as well as Honig3 studied the free vaporization of carbon at very high temperatures and thermochemical properties were evaluated. After this work the hightemperature mass spectrometric method gained wide acceptance and the number of condensed phases studied increased rapidly. Metals, alloys, oxides, sulphides, selenides, tellurides, halogenides, hydroxides, and nitrates were, for example, investigated. Numerous gaseous species were identified and their partial pressures were determined. Thermodynamic data resulted from the partial pressures and their temperature dependences. Most of the vaporization studies were carried out under equilibrium conditions using Knudsen cells.Surveys of recent mass spectrometric investigations on gaseous species and the determination of thermodynamic properties of condensed phases have been given in the review articles by Drowart (1986),4 Gorokhov (1989),5 Hilpert (1989),6 Plante and Hastie (1989),7 and Hilpert (1990.* The special fields of study of ion/ molecule and ion/ion equilibria and the determination of thermodynamic properties for the condensed phase from such data was reviewed in 1986 by Sidorov et al. cles on high-temperature mass spectrometry published before 1986 is given in reference 8.The basis of this article is a lecture given at the Fourth Summer School and Symposium on Mass Spectrometry organized by the Yugoslav Society of Mass Sp...

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Chemistry of inorganic vapors

Hilpert¹

1990

Noble Gas and High Temperature Chemistry

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Thermodynamic Properties of the Melt of the NaI — DyI₃ System

Cited by 9 publications

References 14 publications

Molecular Structure and Vibrational Spectra of Mixed MDyX₄ (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study

Molecular Structure and Vibrational Spectra of Mixed MDyX₄ (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study

High temperature mass spectrometry in materials research

Chemistry of inorganic vapors

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Thermodynamic Properties of the Melt of the NaI — DyI3 System

Cited by 9 publications

References 14 publications

Molecular Structure and Vibrational Spectra of Mixed MDyX4 (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study

Molecular Structure and Vibrational Spectra of Mixed MDyX4 (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study

High temperature mass spectrometry in materials research

Chemistry of inorganic vapors

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Thermodynamic Properties of the Melt of the NaI — DyI₃ System

Molecular Structure and Vibrational Spectra of Mixed MDyX₄ (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study

Molecular Structure and Vibrational Spectra of Mixed MDyX₄ (M = Li, Na, K, Rb, Cs; X = F, Cl, Br, I) Vapor Complexes: A Computational and Matrix-Isolation Infrared Spectroscopic Study