Browsing by Author "Uy, O. M."

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    Experimental Determination of Heats of Formation of Negative Ions and Electron Affinities of Several Boron and Aluminium Fluorides
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Srivastava, R. D.; Uy, O. M.; Farber, Milton
    Thermodynamic properties for the negative ions of boron and aluminium fluorides were obtained by means of the effusion-mass spectrometric method over the temperature range 1100 to 1900 K. Studies were conducted involving negative ions with neutral molecules for the isomolecular reactions BF–2(g)+ F(g)→BF2(g)+ F–(g), BF3(g)+ BF–2(g)→BF(g)+ BF–4(g), AlF2(g)+ F–(g)→AlF–2(g)+ F(g) and 2AlF2(g)+ AlF–2(g)→2AlF(g)+ AlF–4(g). The heats of formation, ΔHf298, for the ions BF–2(g), AlF–2(g), AlF–4(g), and BF–4(g) obtained from the reaction thermodynamics were – 191.7 ± 3, – 232.1 ± 3, – 500 ± 3 and [gt-or-equal]– 433 kcal mol–1, respectively. The electron affinities for BF2 and AlF2 were 50.7 ± 3 and 53.1 ± 3 kcal mol–1, respectively.
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    Mass Spectrometric Determination of the Thermodynamic Properties of the Vapour Species from Alumina
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1972, 68 (2), 1972) Farber, Milton; Srivastava, R. D.; Uy, O. M.
    The vapour species over Al2O3(c) were determined mass spectrometrically from an alumina effusion cell. These data are in good agreement with previously published weight loss data since the partial pressures of the suboxides, AlO, Al2O, AlO2 and Al2O2 were found to be of the same order as those of the elements, Al and O. New values were determined for the ΔHf298K of AlO, Al2O, AlO2 and Al2O2 of 17.0 ± 2.0, –33.2 ± 3.0, –44.3 ± 2.0 and –113.6 ± 2.0 kcal/mol, respectively. Excellent agreement was obtained between second and third law studies.