Salt crystals are common in macromolecular crystallography. Has anyone tried to tabulate salt crystal forms that commonly occur?
I just identified a salt crystal as Mirabilite, made of Na2SO4·10H2O. The high water content makes them rather soft, and may not be recognized as salt right away. In this case, it probably happened because the buffer was made with Na·Citrate + HCl instead of citric acid, while trying to optimize conditions. So, characterization of salt crystals can help to avoid the conditions that cause them. There is probably a reasonably small number of salt crystal forms that are very common in crystallization trials. Maybe it would be useful to tabulate common salt crystals to help guide optimization experiments. Has anyone else tried to use salt crystal information beyond ensuring that it is not protein? Joe Krahn
