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Chapter II Solution Growth….
2.6 Choice of Solvents and Additives
It is important to select proper solvent for the solution growth so that
one can yield prismatic growth habits of crystals. A good solvent ideally
displays the following characteristics:
(a) Moderate reversible solubility
(b) A reasonable positive temperature coefficient of solubility
(c) A small vapor pressure
(d) Non-corrosiveness
(e) Non-toxicity
(f) Low price in a pure state
(g) Non-flammability
Solvents possessing all these characteristics, altogether, do not exist.
However, solvents in practical use include water-both light (H2O) and heavy
(D2O), ethyl alcohol, acetone, carbon tetrachloride, hexane, xylene and many
others. Water is used in about 90% of cases and heavy water, alcohol and
acetone each contributes about 1%.
Usually, a solvent is used in which the solute is soluble to the extent of
10 to 60 %. If the solvent is volatile then precautions must be taken to prevent
volatilization, which promotes spurious nucleation due to temperature and
concentration changes.
The experiments of Bunn and Emmett [42] show that the, electrostatic
forces between crystal and solution are involved in crystal growth and,
therefore, the polarity of the solvent must be considered. Kohman [43] has
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