fusso
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I want some cyanide, should I choose NaCN or KCN?
Which should I choose, concerning factors like solubility, hygroscopicity, cost (per mol!), etc?
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myr
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For what reason, exactly, do you want cyanide for?
KCN is cheaper on Sigma-Aldrich.
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DoctorOfPhilosophy
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I can think of some use cases where it wouldn't matter  For gold extraction,
Wikipedia suggests calcium cyanide
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fusso
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One rxn I want to try is making nitriles. Also I'm worried new
legislations may be made to ban them in my country so I want to get some ASAP before they are banned. I favour other suppliers over SA as it's the
most expensive.
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clearly_not_atara
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I would consider CuCN or Zn(CN)2 as they're much safer to handle and, IIRC, cyanide can be recovered by dissolving in ammonia and reducing with Mg. In
particular, Zn(CN)2 can be used directly in the Gattermann reaction.
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fusso
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So is Ca cyanide the cheapest cyanide salt? If yes then I can see why is
Ca cyanide used to extract gold.
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DoctorOfPhilosophy
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I dug deeper into this. Apparently it started during WWI when the European supply of NaCN was cut off and we started making it locally but with
calcium instead (https://dr.library.brocku.ca/handle/10464/9781?show=full). The manufacturing process also seems easier, being a continuous one step process (https://www.911metallurgist.com/blog/cyanide-gold-dissolutio...).
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ninhydric1
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Calcium cyanide can be easily converted to NaCN or KCN using sodium or potassium sulfate, filtering out the calcium sulfate and boiling down the
filtrate, so it is pretty versatile.
The philosophy of one century is the common sense of the next.
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Herr Haber
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I'd go straight for the salt that I need for what I want to do.
If several options are available then my other criteria would be solubility.
I am not concerned about using the salt or a solution but I'd rather avoid unnecessary manipulation in this case.
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