Crystallization

Crystallization is a phase transition that takes place from the liquid toward the solid state resulting in the formation of crystals; less frequently, the deposition of crystals can also occur starting from the gas state. In any case, crystallization process represents a particular kind of solidification in which the molecules or ions of a given substance arrange themselves in an orderly fashion according to a substance-specific three-dimensional lattice. Differently, in the absence of orderly arrangement, solidification process leads to amorphous precipitates or to solids consisting of a mix of crystalline and amorphous areas (as it happens for some polymers). Crystallization takes place when the solution containing the substance to crystallize reaches the supersaturation state, namely, when the concentration of this substance overcomes the solubility limit while remaining below the threshold of precipitation. The kinetics and the thermodynamics of the crystallization depend on the...