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Re: [ccp4bb] Characterization of common salt crystal forms?
 

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CCP4bb <-- 2008 <-- January 2008 <-- 23 January 2008
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Subject: Re: salt sensitive complex
From: David Briggs drdavidcbriggs {- at -} GMAIL {- dot -} COM
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Subject: Re: Characterization of common salt crystal forms?
From: David Briggs drdavidcbriggs {- at -} GMAIL {- dot -} COM
Date: 2008-01-23
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 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
>


--
============================
David C. Briggs PhD
Father & Crystallographer
http://www.dbriggs.talktalk.net
AIM ID: dbassophile
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