Growth of tetragonal lysozyme crystals from solutions containing NaCl, CsCl and NaNO3

It is shown that crystals of one modification can also grow with a precipitant, in whose presence crystals of another modification are formed spontaneously, with no noticeable changes of the surface morphology observed. Experiments were carried out in situ using the phase contrast microscope that, unlike probe microscopes, allowed any influence on the surface under examination to be avoided. The dissolution enthalpy of a tetragonal crystal in a solution with NaNO3 is equal to, within an experimental error, to the dissolutions of a tetragonal crystal in a solution with NaCl. The significance of this fact is discussed. It is confirmed that at a comparatively low supersaturation, the growth islands are formed prior to the formation of dislocation hillocks because of a local decrease in the surface energy due to the adsorption of impurity particles. The equilibrium temperature for monoclinic crystals in the solution containing NaCl is found.