Über thermische Eigenschaften von Halogeniden. 10. Dampfdrucke und Dampfdichten von Gallium III‐Halogeniden

Fischer, Werner; Jübermann, Otto

doi:10.1002/zaac.19362270303

Cited by 69 publications

(15 citation statements)

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“…To optimize technological pro cesses using GaCl 3 , one should enhance the accuracy of the thermodynamic characteristics of matter description and extend the temperature interval of the thermody namic data presented in the literature. [1][2][3][4][5] The purpose of the present study is to obtain reliable information on the thermodynamics of sublimation, fusion, vaporization, and association of GaCl 3 .…”

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confidence: 99%

Thermodynamics of vaporization of gallium trichloride

et al. 2007

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The unsaturated and saturated pressures of gallium trichloride vapor were measured by the static method with membrane gauge manometers in wide pressure (0.2-760 Torr) and tem perature (313-1071 K) intervals. Scanning calorimetry was used to determine the thermo dynamic characteristics of GaCl 3 fusion. The thermodynamic characteristics were obtained for sublimation, fusion, vaporization, and association in the vapor of GaCl 3 molecules. The enthalpies of formation and the absolute entropies of GaCl 3 in the liquid and gaseous phases and Ga 2 Cl 6 in the gaseous phase were calculated using literature data.Key words: gallium trichloride, vapor pressure, enthalpy of sublimation, entropy of subli mation, enthalpy of vaporization, entropy of vaporization, entropy of association.Gallium trichloride is the starting reagent for growing single crystals of semiconductors of the A III B V type and related solid solutions. In the recent years, GaCl 3 found use as the catalyst in the synthesis of organic and orga nometallic compounds. To optimize technological pro cesses using GaCl 3 , one should enhance the accuracy of the thermodynamic characteristics of matter description and extend the temperature interval of the thermody namic data presented in the literature. 1-5 The purpose of the present study is to obtain reliable information on the thermodynamics of sublimation, fusion, vaporization, and association of GaCl 3 . ExperimentalThe main difficulty in experimental studying the thermody namic properties of GaCl 3 is caused by the high hygroscopicity of the compound. Therefore, we gave special attention to prob lems of synthesis, purification, and packing of the samples.The studies were carried out for the samples prepared by both the authors of the present work and coworkers of the S. I. Vavilov State Optical Institute. The both batches of the substance were synthesized using a standard procedure by the "combustion" of metallic gallium in a chlorine flow. 6 The prod ucts were purified by vacuum sublimation (in this case, volatiles were frozen with liquid nitrogen) or fusion in dynamic vacuum. According to the results of chemical, X ray diffraction, and spectral analysis, the both batches of the substances repre sented the individual phase of GaCl 3 of stoichiometric composi tion in which the total content of admixtures did not exceed 0.01 wt.%.Samples for both calorimetric and tensimetric studies were packed using distillation in a closed evacuated system.Calorimetric measurements were carried out with a Setaram DSC 111 scanning calorimeter at heating rates of 1-3 K min -1 . Weighed samples of the substance were 20-30 mg and during experiments were placed in evacuated glass ampules. The error of determination of the thermal effects did not exceed 2% of the determined value.Tensimetric studies were performed by the static method using quartz membrane gauge manometers. Errors in tempera ture measurements determined from calibrations by reference substances (indium, tin, lead, and antimony were used for the calibration of the...

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confidence: 99%

Thermodynamics of vaporization of gallium trichloride

et al. 2007

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“…As indicated in the literature,1–5 the gallium trichloride saturated vapor consists of dimeric molecules and a small quantity of monomeric molecules.…”

Section: Resultsmentioning

confidence: 87%

“…In the available articles1,2 similar experimental data are expressed by the slightly curved lines. The cause of this phenomenon can be explained by the association processes taking place in liquid gallium trichloride.…”

Section: Resultsmentioning

confidence: 99%

“…Such data is important for obtaining semiconductors on the basis of gallium compounds of given composition by deposition from the gaseous phase. For the dependence of the unsaturated vapor pressure on temperature1–5 only few publications are available in the literature. They suggest the existence of dimeric molecules and their dissociation according to the reaction Ga 2 Cl 6 (g) = 2GaCl 3 (g).…”

Section: Introductionmentioning

confidence: 99%

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On the Existence of the Trimer of Gallium Trichloride in the Gaseous Phase

Tsirel'nikov

Lokshin

Melnikov

2012

Zeitschrift anorg allge chemie

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The dependence of the gallium trichloride saturated and unsaturated vapor pressures on temperature was studied by the static method using a quartz membrane zero-manometer and taking into account the volume of its working chamber and substance mass. Conclusions about the presence of a distinguishable amount of trimeric molecules along with dimeric and momomeric molecules in the vapor were drawn on the basis of the obtained data. The following rough thermo-

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“…bEvaluated from the log K(T) for the reaction GaC13 + H 2 = GaC1 + 2HC1 in [91 (calth = 4.184J). alnterpolation of values of log K(T) for the reactions Ga2C16 = 2GaC13 [17] and 2GaCI = Ga2C12 [19] (calth = 4.184J).…”

Section: Thermodynamic Considerationsmentioning

confidence: 99%