Thermodynamics of insertion, AG, AS, AH

Compounds made by insertion at room temperature are often metastable - if heated, they change their structure or decompose into other compounds. That does not rule out using thermodynamics it just means that processes happening slowly compared to the duration of an experiment are assumed to be frozen. At room temperature, the ratio of Mo to Se in a host like Mo Seg is fixed. From the point of view of thermodynamics, the constraint that the host remain Mo Seg means that we can regard an intercalation compound like Li -MogSeg as a pseudo-binary compound instead of a ternary one. 

When this constraint breaks down, the solid decomposes. The decomposition can be described in a higher-dimensional phase diagram that considers the guest and all the components of the host on an equal footing (Godshall, Raistrick and Huggins, 1980). It can be difficult to 

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