ࠗ w This paper contains enhanced objects available on the Internet at http://pubs.acs.org/crystal. ABSTRACT: A comparison between a priori model predictions and experimental results for crystal shapes of succinic acid crystals dissolving in aqueous solution is presented. The model is the simplest possible model which neglects all effects other than a determination of which faces to include on the crystal habit and their perpendicular growth rates. The experiments are carried out in a thermostatted peltier cell and are imaged in situ using a microscope with digital imaging capabilities. The predicted and experimentally measured crystal shapes are very similar throughout the dissolution process. Thus, the experiments provide support for the model's predictive power.The change in crystal shape as a result of dissolution is a topic of interest for a wide range of materials including organics such as pharmaceuticals, proteins and specialty chemicals as well as inorganics in geology and semiconductors. For inorganic and organic materials, dissolution not only affects the crystal shape but also plays a vital role in polymorphic phase transformations. The possible end-shapes in crystal dissolution have been discussed in many contexts. 1-4 For example, Moore suggested that vertices on growth shapes would end up as faces on dissolution shapes, 2 and Gibbs suggested that shapes in dissolution will differ from the equilibrium form in a direction "opposite" to that of growth. 3 Despite these qualitative descriptions, a model that can quantitatively predict the evolution of crystal shapes during dissolution has only recently been developed. 5 This communication presents recently produced in situ experimental confirmation of the model's predictions for the dynamics of dissolving crystal shapes, along with the related modeling information necessary for comparison.We have chosen -succinic acid crystals dissolving in water as the system to demonstrate the effective predictions of the model. The crystallization and subsequent dissolution and visualization were performed in a thermostatted peltier cell equipped with a Nikon microscope and digital imaging capabilities, and has been previously described in detail. 6 A saturated solution of -succinic acid 7 in 2 mL of water was prepared at a saturation temperature of 36°C. Nucleation was induced at a lower temperature (25°C). Once a crystal could be observed in the solution, the temperature was raised to within a degree of saturation, and the crystal was allowed to grow to a size suitable for dissolution visualization (∼100 µm). Then, the temperature was increased to one degree above saturation, leading to dissolution during which the crystal shape evolution was recorded. Since the mass of the dissolving crystal is very small (∼0.001 mg compared to the 2 mL volume of the crystallizer) the undersaturation is approximately constant throughout the dissolution process.The model for shape evolution can predict and track each of the faces of a fully three-dimensional crystal during growth an...