crystal chemistry

Crystallization - This technique is used for obtaining a compound in pure solid form of well-defined geometrically shaped crystals. This process of crystallization can be used for the purification of a compound only when the compound and the impurities present in it di..

Crystals are solid particles bounded by plane surfaces, which make definite angles with each other. This gives a definite geometrical shape to the crystal. These shapes are different for different crystals (Fig.6.13). Crystals of the same substance are ..

This method is used to separate a solid compound in pure and geometrical form. A nearly saturated solution of an impure substance is prepared in a hot solvent. The prepared solution is quickly filtered and the filtrate is then allowed to cool slowly in a china dish. The resulting pure crystal..

Separation of the Constituents of Mixtures - Crystallization - Crystallisation is the process by which crystals are obtained from a saturated solution of a substance, by allowing the solvent to evaporate slowly. If there are any insoluble impurities in the solution, they can be ..

When the crystals are unstable, they are gently pressed between the folds of filter papers, and are finally placed in a vacuum desiccator to obtain dry crystals. If the substance is stable and has a high melting point, the crystals are pressed between the fold of the ..

If the impure compound is a mixture of two compounds whose solubility in any solvent does not differ significantly from one another, then the two compounds are separated by fractional crystallization. This is a series of repeated crystallisations. For instance when a solution containing ..

In molecular crystals, the constituent particles are molecules. These molecules are held together by weak forces known as Van der Waal's forces. Common examples are dry ice, wax, iodine, sulphur, etc. Characteristic features of molecular crystals are: Molecular crystals..

When certain salts form crystals with a definite number of molecules of water, they chemically combine to do so in a definite proportion. Thus, the water of crystallisation is the number of water molecules that combine chemically in definite molecular proportion, with the concerned ..

In metallic crystals the constituent particles are positive kernels i.e., nuclei where inner electrons are dispersed in a sea of mobile valence electrons. The forces present between the constituents are metallic bonds. The main characteristics of metallic crystals are: Metalli..

This method is used to separate two or more solutes, by making use of their difference in solubility. If we want to separate potassium nitrate from a mixture that contains about 80 g of potassium nitrate and 20 g of sodium chloride. We will dissolve this mixture in about 100 g of water and then hea..