High-Temperature Vaporization and Thermodynamics of the Titanium Oxides. VII. Mass Spectrometry and Dissociation Energies of TiO(g) and TiO2(g)

Journal of Chemical Physics - Tập 55 Số 8 - Trang 3712-3729 - 1971
Peter Hampson1, Paul W. Gilles1
1Department of Chemistry, University of Kansas, Lawrence, Kansas 66044

Tóm tắt

Two experiments of the successive vaporization type, five mass spectrometric vaporization experiments, and two isomolecular exchange reaction experiments were undertaken to resolve discrepancies in the thermodynamics of the titanium—oxygen system. The first two types of experiments confirmed that Ti3O5(s) is the congruently vaporizing phase. The second type of experiment showed that the principal reaction accounting for the congruent vaporization is Ti3O5(S)=TiO(g)+2TiO2(g). In the third type of experiment, measurements on the isomolecular exchange reaction TiO(g)+Sc(g)=Ti(g)+ScO(g) showed that the dissociation energy of TiO(g) is smaller than that for ScO(g) and on the basis that D0o(ScO) is 160.4±2.0 kcal/mole, D0o(TiO) becomes 156.9±2.2 kcal/mole, or 6.80±0.10 eV. This result may be combined with earlier vapor pressure measurements on Ti3O5(s) and the congruency condition to yield D0o(TiO2)=311.7±1.8 kcal/mole, 13.52±0.08 eV, or very nearly twice D0o(TiO). One of the two previously discussed discrepancies in the thermodynamics of the titanium oxides appears to have been resolved, and the likely resolution of the other is discussed.

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Tài liệu tham khảo

1967, J. Chem. Phys., 46, 2461, 10.1063/1.1841070

1957, J. Phys. Chem., 61, 1569, 10.1021/j150557a027

1967, J. Chem. Phys., 46, 2465, 10.1063/1.1841071

1955, J. Phys. Chem., 59, 127, 10.1021/j150524a008

1967, J. Chem. Phys., 46, 4987, 10.1063/1.1840670

1969, J. Chem. Phys., 50, 1046, 10.1063/1.1671099

1969, J. Chem. Phys., 50, 1048, 10.1063/1.1671100

1957, Acta Chem. Scand., 11, 1653, 10.3891/acta.chem.scand.11-1653

1965, J. Chem. Phys., 42, 1033, 10.1063/1.1696039

1967, J. Phys. Chem., 71, 2707, 10.1021/j100867a049

1967, Trans. Faraday Soc., 63, 2140, 10.1039/tf9676302140

1967, J. Chem. Phys., 46, 1646, 10.1063/1.1840917

1956, J. Am. Chem. Soc., 78, 546, 10.1021/ja01584a009

1965, Trans. Faraday Soc., 61, 1072, 10.1039/TF9656101072

1963, J. Phys. Chem., 67, 762, 10.1021/j100798a010

1969, Trans. Faraday Soc., 65, 98, 10.1039/tf9696500098

1966, Rev. Hautes Temp. Refractaires, 3, 229

1953, J. Inst. Metals, 82, 87

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Thông tin xuất bản

Journal of Chemical Physics

Tập 55 Số 8

3712-3729

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