Final answer:
The ideal solvent for crystallization is one that is more soluble at high temperature than at low temperature, allowing the compound to crystallize out of solution. The impurities should be more soluble and present in small amounts.
Step-by-step explanation:
The ideal solvent for crystallization of a particular compound is one that is more soluble at high temperature than at low temperature. This allows the compound to crystallize out of solution when the temperature is lowered. Additionally, the impurities should be more soluble than the compound of interest and present in small amounts. The choice of solvent will depend on the specific compound and its solubility characteristics.