<Li> Specialized equipment can be used in the shape of a "H" to perform the above, where one of the vertical line of the "H" is a tube containing a solution of the compound, and the other vertical line of the "H" is a tube containing a solvent which the compound is not soluble in, and the horizontal line of the "H" is a tube which joins the two vertical tubes, which also has a fine glass sinter that restricts the mixing of the two solvents . </Li> <Ul> <Li> Once single perfect crystals have been obtained, it is recommended that the crystals are kept in a sealed vessel with some of the liquid of crystallisation to prevent the crystal from' drying out' . Single perfect crystals may contain solvent of crystallisation in the crystal lattice . Loss of this internal solvent from the crystals can result in the crystal lattice breaking down, and the crystals turning to powder . </Li> </Ul> <Li> Once single perfect crystals have been obtained, it is recommended that the crystals are kept in a sealed vessel with some of the liquid of crystallisation to prevent the crystal from' drying out' . Single perfect crystals may contain solvent of crystallisation in the crystal lattice . Loss of this internal solvent from the crystals can result in the crystal lattice breaking down, and the crystals turning to powder . </Li> <P> For ice, recrystallization refers to the growth of larger crystals at the expense of smaller ones . Some biological antifreeze proteins have been shown to inhibit this process, and the effect may be relevant in freezing - tolerant organisms . </P>

What are two characteristics of a good recrystallization solvent for a given compound