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Heat capacity equations for nonstoichiometric solids

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Abstract

The equations for heat capacity measured under isodynamical conditions (fixed activity of a single component) are derived for partly open systems exchanging one component with the surroundings while keeping the contents of all other components constant. Compared to conventional isobaric (and isoplethal) heat capacity of a strictly stoichiometric phase, the isodynamical heat capacity of a nonstoichiometric phase is found to involve two additional terms—the saturation contribution due to incorporation (or release) of the free component and the contribution due to deviation from stoichiometry reflecting a different number of the involved phonon modes (due to different free component content) and in some cases a variation of free component incorporation mechanism.

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Acknowledgements

One of the authors, P. Holba, acknowledges a support of the CENTEM project, reg. no. CZ.1.05/2.1.00/03.0088, that is co-funded from the ERDF within the OP RDI program of the Ministry of Education, Youth and Sports.

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Authors and Affiliations

  1. New Technologies—Research Centre, University of West Bohemia, Universitní 8, 30614, Pilsen, Czech Republic

    P. Holba

  2. Department of Inorganic Chemistry, Institute of Chemical Technology, Technická 5, 16628, Prague, Czech Republic

    D. Sedmidubský

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  1. P. Holba
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  2. D. Sedmidubský
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Correspondence to P. Holba.

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Holba, P., Sedmidubský, D. Heat capacity equations for nonstoichiometric solids. J Therm Anal Calorim 113, 239–245 (2013). https://doi.org/10.1007/s10973-012-2886-1

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  • DOI: https://doi.org/10.1007/s10973-012-2886-1

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