Phenomena leading to solid-gas equilibriums

Phenomena that occur diuing heating of a solid can lead to solid-gas equilibriums. These are as follows  

We will study these phenomena from the thermodynamic point of view, but for that, it is convenient to provide a classification from their thermodynamic characteristics and in particular the variance of the system. 

The systems considered include (p phases and a gas phase (gases are miscible in all proportions). The number of solid phases 97 thus will be  

Most commonly, transformations involve one of the following three classes. 

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