Formation molar Gibbs energy of clusters

We have noted that the driving force of creation of a solid is super-saturation, and that the clusters that are the obliged intermediates correspond in states of energy higher than those of the infinite solid. It is conceived intuitively that super-saturation and interfacial energy are the two dominating terms in the creation of the nuclei. 

We can adopt the traditional terminology the clusters constitute the reactional way. The nucleation that is done starting from a system initially free from formed solid is known as primary nucleation . If it occurs in the bulk of an initial phase, it is homogenous either in fluid environment or in solid medium. The nucleation that is done in contact with a solid phase is known as heterogenous nucleation , and it occurs at the interface between reactant that constitutes different phases. 

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