Supersaturation And Supercooling

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1) Achievement of supersaturation or supercooling 2) Formation of crystal nuclei 3) Successive growth of crystals to get distinct faces Ostwald’s Diagram Ostwald was appeared to be the first to explain the relationship between supersaturation and spontaneous crystallization. The relationship between the concentration and temperature is schematically shown in Figure 1. Extensive research has been carried out to explain the relationship between supersaturation and spontaneous crystallization. The lower continuous line is the normal solubility curve for the salt concerned. Temperature and concentration at which spontaneous crystallization occurs have been represented by the upper broken curve, generally referred to as the supersolubility …show more content…

R = F (t, s, pH, c) Where R expresses the growth rate of the crystal and t, s, c express the temperature, supersaturation and concentration of impurity respectively, in the solution. Different crystal faces have grown at different rates under varying environmental conditions. Growth of good quality single crystals by slow evaporation and slow cooling techniques have required optimize conditions. These are (i) material purification, (ii) Solvent selection, (iii) solubility, (v) seed preparation, (vi) agitation, (vii) crystal habit and (viii) cooling rate. Material Preparation Material which have been used for crystal growth should be highly pure. Solute and solvents of high purity have required, since impurity may be incorporated into the crystal lattice have resulted in the formation of flaws and defects. Sometimes impurities may slow down the crystallization process by being adsorbed on the growing face of the crystal, which changes the crystal

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