During the heterogeneous nucleation process, which is of interest in this review, the variation in Gibbs energy (owing to the critical radius of the crystal) occurs because of the interaction of the nucleus/clusters in the solution acting as monomers during nucleation and crystal growth . Hence, these clusters play a critical role in reaching a specific geometric arrangement, which creates a minimization of the surface energy . In this way, the crystal stability depends on the size of the critical radius; usually, those with smaller dimensions tend to be unstable and therefore are more likely to dissolve in solution and recrystallize about larger nuclei that are relatively more stable. This physical mechanism is known as Ostwald Ripening (OR) .