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Thermodynamic Assessment of P 2 O 5
Author(s) -
Jung InHo,
Hudon Pierre
Publication year - 2012
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2012.05382.x
Subject(s) - gibbs free energy , bar (unit) , metastability , thermodynamics , phase diagram , triple point , chemistry , chemical stability , liquid phase , materials science , crystallography , phase (matter) , physics , organic chemistry , meteorology
All the thermodynamic property data and phase diagrams related to solid and liquid P 2 O 5 were critically evaluated and optimized to obtain the best set of Gibbs energies for all phases. Confusion in literature data due to the very sluggish nature of the reactions involving P 2 O 5 was resolved. The Gibbs energies of O ‐ and O′ ‐ P 2 O 5 were evaluated for the first time based on the phase stability against gas. The Gibbs energy of liquid H ‐ P 2 O 5 , liquid O ‐ P 2 O 5 , and liquid O′ ‐ P 2 O 5 were also properly evaluated for the first time based on the metastable and stable vapor pressures. The calculated triple points of H ‐ P 2 O 5 , O ‐ P 2 O 5 , and O′ ‐ P 2 O 5 are 420°C and 4.600 bar, 575°C and 0.805 bar, and 580°C and 0.774 bar, respectively. The calculated polymorphic transition point between O ‐ P 2 O 5 and O′ ‐ P 2 O 5 is located at 65°C and 0.001 bar.