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Crystallization is the process by which solids form, where the atoms or molecules are highly organized into a structure known as a crystal. Some ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.
The stopper can be used to protect the solution from atmospheric contamination. The crystals are separated from the mother liquor by placing the tube and stopper – inverted – in a centrifuge tube, followed by centrifugation. The stopper allows the mother liquor to pass into the centrifuge tube but retains the crystals, which can ...
In chemistry, fractional crystallization is a stage-wise separation technique that relies on the liquid–solid phase change. This technique fractionates via differences in crystallization temperature and enables the purification of multi-component mixtures, as long as none of the constituents can act as solvents to the others. Due to the high ...
The methods used to determine the degree of crystallinity can be incorporated over time to measure the kinetics of crystallization. The most basic model for polymer crystallization kinetics comes from Hoffman nucleation theory. The crystallization process of polymers does not always obey simple chemical rate equations. Polymers can crystallize ...
Fractionation is also used for culinary purposes, as coconut oil, palm oil, and palm kernel oil are fractionated to produce oils of different viscosities, that may be used for different purposes. These oils typically use fractional crystallization (separation by solubility at temperatures) for the separation process instead of distillation.
The flux method is a crystal growth method where starting materials are dissolved in a solvent (flux), and are precipitated out to form crystals of a desired compound. The flux lowers the melting point of the desired compound, analogous to a wet chemistry recrystallization. [1]
All crystals have translational symmetry in three directions, but some have other symmetry elements as well. For example, rotating the crystal 180° about a certain axis may result in an atomic configuration that is identical to the original configuration; the crystal has twofold rotational symmetry about this axis.
Crystallography is used by materials scientists to characterize different materials. In single crystals, the effects of the crystalline arrangement of atoms is often easy to see macroscopically because the natural shapes of crystals reflect the atomic structure. In addition, physical properties are often controlled by crystalline defects.