Hi Joe,
I've known most salt crystals in Phosphate - and I think most people
are weary of phosphate.
Also, Calcium Sulphate is a fairly common one, esp if your buffers are
titrated with sulphuric acid. Fluoride Ions are also prone to form
salt crystals with transition metal ions.
HTH,
Dave
On 22/01/2008, Joe Krahn <[log in to unmask]> wrote:
> 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
>
--
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David C. Briggs PhD
Father & Crystallographer
http://www.dbriggs.talktalk.net
AIM ID: dbassophile
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