Homogeneous reactions in the solid state

Reaction (2-1) proceeds as a homogeneous reaction until the crystal has achieved a new minimum of the total free energy as given by the temperature dependent equilibrium constant of eq. (2-1)  

By means of diffusional steps in the interstices, the ions of the one sublattice seek out the vacancies in the other sublattice, and a reversal of positions occurs. In this way, equilibration is achieved. 

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