fluorescence
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KCN and Chalcogens (?)
So I was preparing a few additional videos for youtube. A new topic I introduced was the reaction between hot KCN solutions and the Chalcogens.
- For Tellurium I was able to dissolve some elemental Tellurium in boiling KCN. Then I added a few drops of HCl (like the literature suggests) and the
black Tellurium formed again (funnily without producing HCN so this reaction seems to be favored).
Now I thought it should be KTeCN of course as you can make these K(chalc)CN compounds by fusing the reactants. But on the other hand I found a lot of
literature suggesting K2Te might form. And it seems like adding acid to K2Te does not even produce that much H2Te as
you might expect but a lot of Te as well. So I can't really distinguish between the two.
- Then I did the same for Selenium. Here red Selenium formed. I was a bit surprised as I always thought KSeCN is stable in dilute acid. But usually
you fuse the Se with KCN dry to make it and not boil it in water. So it might be something else as well.
- Last I did it for Sulfur and here nothing happened when I added the acid. But when I added FeCl3 it turned dark red. So here a
Thiocyanate might have really formed.
So maybe it's just the tendency like I read that Te doesn't only form Polytellurides in NaOH like Sulphur would do but Tellurites and Tellurates as
well, so there seems to be abit more happening whenever you work with Tellurium.
Now I can't find much on the topic but perhaps somebody has a bit more experience here. Does anyone know what really form if Se and Te are boiled in
KCN (not fused!) ?
[Edited on 14-4-2017 by fluorescence]
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Boffis
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@ fluorescence; I can't answer your question but recently while checking out some references in the Acta. Chem. Scandinavia journal I noticed numerous
papers by a small group of authors on exactly these sorts of tellurium compounds. I suggest you check out their web site, you can download paper for
free and there are many dealing with tellurocyanates, tellurosulphates etc.. I think you will find lots of interesting stuff there,.
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Boffis
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Hi Fluorescence: attached are a couple of papers I downloaded from he Scandinavian chemical journal web site that might be of interest to people who
like tellurium:
Attachment: acta_vol_25_p0331-0333.pdf (412kB)
This file has been downloaded 282 times
Attachment: acta_vol_03_p0708-0716.pdf (803kB)
This file has been downloaded 286 times
There are many more papers alone these lines and also a lot of information on the analogous selenium compounds.
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