Glossary of Terms for Phase Equilibria Diagrams

A B C D E G H I J L M P S T V

Metastable Phase
Monotropic Forms

  • Metastable Phase
    A phase exists metastably in a system if it would not be present at final (thermodynamic) equilibrium, under unchanged conditions, and if the system is not approaching thermodynamic equilibrium at an observable rate.

    Reference: Levin, E.M., McMurdie, H.F., and Hall, F.P., Phase Diagrams for Ceramists: Volume 1, The American Ceramic Society, Columbus, Ohio, p. 7, 1956.



  • Monotropic Forms
    In certain instances of polymorphism, the vapor-pressure curves of the two forms do not meet below the melting point. They, therefore, lack a stable inversion point, and the form with the higher vapor pressure is metastable with respect to the other at all temperatures below the melting point. Such forms are called monotropic and are not interconvertible.

    Reference: Levin, E.M., McMurdie, H.F., and Hall, F.P., Phase Diagrams for Ceramists: Volume 1, The American Ceramic Society, Columbus, Ohio, p. 7, 1956.






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Date created: 08 February 2001
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