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Author: Subject: Small amount of cyanide in Europe?
Bubbles
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[*] posted on 12-1-2022 at 10:04
Small amount of cyanide in Europe?


Hi,

I am looking for a bit of (sodium or potassium) cyanide. Like ~100 grams.
Is there someone in Europe who could send me some for a reasonable price?

I could also trade. For example I have more sodium borohydride than I need (with 1% NaOH! but this is usually not a problem and can always be neutralized). Also other stuff.

Best,
Bubbles
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MidLifeChemist
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[*] posted on 12-1-2022 at 18:18


I always thought 2 grams was a bit. 100 grams of a compound is a windfall! :)
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teodor
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[*] posted on 13-1-2022 at 03:29


That's probably how the mind of an inorganic chemist differs from the mind of an organic chemist. When I was asking sellers about cyanide I also referred to 100g as a "some huge amount".
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woelen
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[*] posted on 14-1-2022 at 00:06


A 100 grams of cyanide is a huge amount for one application, while being only a little amount for another application.

I myself have done photography developing. In the past, potassium cyanide was used as a fixing bath in some processes. Nowadays, if people still do their own development of latent images, sodium thiosulfate or ammonium thiosulfate is used for fixing purposes. But a fixing bath requires tens of grams of chemical for a single bath. So, if you do some regular photography, then you easily use up 100's of grams of fixing agent.

On the other hand, if you use it to commit suicide, then you only need 300 mg or so, and usually only one time :P ;)




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teodor
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[*] posted on 14-1-2022 at 03:56


That means that the man who asks for 1kg+ has no depression.

But being a photographer in the past I am wondering what are the benefits of cyanide as a fixing bath?
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[*] posted on 14-1-2022 at 04:26


potassium cyanide is usefull for electroplating of silver too. The Size of your substrate give the amount of cyanide needed in your bath.

[Edited on 14-1-2022 by brubei]




I'm French so excuse my language
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Bubbles
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[*] posted on 14-1-2022 at 05:07


I like to be well stocked :D
I don't know what I will use it for first, but I've seen it being used quite often in interesting syntheses.

I moved and now am constructing a basement lab, with a fume hood. So much better than mistreating my kitchen.
Now I feel safe enough working with cyanide.

I found someone willing to trade for my borohydride so not looking for it anymore.
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woelen
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[*] posted on 18-1-2022 at 00:06


Quote: Originally posted by teodor  
That means that the man who asks for 1kg+ has no depression.

But being a photographer in the past I am wondering what are the benefits of cyanide as a fixing bath?
Using cyanide for a fixing bath nowadays has no benefit at all. Thiosulfate is cheaply available at very high purity and virtually non-toxic, so that is the preferred compound to use.

In the past, however, thiosulfates were not that easily available and the product could contain a small amount of sulfide. Even an amount of less than e.g. 0.01% already gives a noticeable brown fog on silver halide papers. Thiosulfate was made by boiling sulfur in concentrated NaOH, which leads to a disproportionation reaction, in which thiosulfate and sulfide is formed. Tiny amounts of sulfide could be left in the thiosulfate. I don't know how they make thiosulfate nowadays, but the product we can buy now is really free of sulfide, which is very important for photographic purposes. It may contain some sulfite or sulfate, but that is no problem, when it is used as fixing agent.




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[*] posted on 18-1-2022 at 06:57


Quote: Originally posted by woelen  

In the past, however, thiosulfates were not that easily available and the product could contain a small amount of sulfide. Even an amount of less than e.g. 0.01% already gives a noticeable brown fog on silver halide papers. Thiosulfate was made by boiling sulfur in concentrated NaOH, which leads to a disproportionation reaction, in which thiosulfate and sulfide is formed. Tiny amounts of sulfide could be left in the thiosulfate. I don't know how they make thiosulfate nowadays, but the product we can buy now is really free of sulfide, which is very important for photographic purposes. It may contain some sulfite or sulfate, but that is no problem, when it is used as fixing agent.


According to wiki:

On an industrial scale, sodium thiosulfate is produced chiefly from liquid waste products of sodium sulfide or sulfur dye manufacture.

We did on high school sodum thiosulfate from sodium sulfite and sulfur. This reaction produce only thiosulfate without any byproducts.




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woelen
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[*] posted on 18-1-2022 at 12:04


Interesting, so nowadays, they oxidize sulfide. Apparently the thiosulfate nowadays is separated from remnants of sulfide very well. My thiosulfate really is free of sulfides, otherwise I would certainly have noticed it.

So, indeed, nowadays there is no point at all in using cyanide for photographic fixing purposes anymore, also not from a financial point of view.




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