Asked in GeologyChemistryEarth Sciences
How does temperature affect the growth of crystals?
February 09, 2012 1:31PM
Crystal growth and nucleation, where nucleation is the formation of a solid phase from a solution, are controlled by a thing called 'supersaturation'. Supersaturation is when the concentration of a species in solution is greater than what it would theoretically be at equilibrium. An example of supersaturation is dissolving table salt in water. A point will be reached when the water is 'saturated'. Any further salt added at this point will not dissolve. The solution is now 'supersaturated'.
Supersaturation is also dependent on the solubility of the species in question. As the solubility of the species increases, then the supersaturation decreases. Depending on the properties of the species, increasing temperature will increase or decrease the solubility of the species in solution, hence increasing or decreasing the supersaturation.
The degree of supersaturation controls whether the reaction is nucleation or growth controlled. A nucleation controlled crystallisation will generally have smaller particles than one that is growth driven.
If looking at cooling a solution, in general, the crystals that have rapidly cooled will be smaller than the ones that have cooled over a longer period of time. Like when you try to make crystals in the refrigerator, the crystals will grow faster but in smaller pieces stuck together. But if you make crystals in room temperature, the crystals will grow slower and in big chunks.sike i was just kidding none of this is true crystals really just grow on their own untill they cvan start there own family then the cycle will start all over again.