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vano
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[*] posted on 23-3-2021 at 04:40
My selenium compounds


Hi. When I was newly registered I made a mistake and now the information on selenium compounds is scattered, I decided to continue the synthesis of selenium compounds and plus I will gather my articles here because If anyone is interested years later find it easy.

Cu, Ni and Mn selenites + photo
Scandium selenite and new manganese selenite + photos
Cobalt selenite + photos
Cadmium polychalcogenides? + Photo /sulfur and selenium
Selenides easy preparation method
Mercury selenite
________________________________________________________________________
•Also i made indium selenite, its white, but its just for my selenites colection. Scandium salt is also white, but ot is a very rare compound and i dont care about colour.

received_979125346246562.jpeg - 197kBPicsArt_03-23-04.28.07.jpg - 297kB

•This is a barium selenide. It has very beautiful colour, i have much more in ampoule, but not here.

received_292862398854900.jpeg - 132kB

•I made small amount of red and black selenium, they aren't for reactions, because i always use granules. Red one i made from hydrolysis of green polysenenium cation. I dissolved granules in hot concentrated H2SO4. next i heat some red selenium and made black. Should be heated but should not be melted.

received_225498512693581.jpeg - 177kB

•This is cadmium polyselenide, just a fact it changed colour and get darker. Above is a link to compare.
received_3723116557806527.jpeg - 155kB

•And boring Pb and Ni Selenides.
received_153015860012516.jpeg - 327kB

This is part of the selenium compounds which I found this time.


[Edited on 23-3-2021 by vano]




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vano
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[*] posted on 23-3-2021 at 04:44


Just nice photo of Selenites.

PicsArt_02-11-05.41.21.jpg - 129kB




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[*] posted on 23-3-2021 at 16:14


Very nice! I always click on your posts, to see what new colors you've come up with.
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[*] posted on 23-3-2021 at 23:10


Thanks!



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[*] posted on 25-3-2021 at 06:32


I wonder how l;ong your red selenium will remain red. I made an ampoule of red selenium myself, but now it almost lost its color and is dark grey. It is as if the saturation of the color slowly is turned down, like colors on an old-fashioned color TV could be turned down, until you just had black and white (grey levels).



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[*] posted on 25-3-2021 at 06:50


When I made it, it had a very nice red color, it gradually became darker. After some period when it loses its red color I will write here.



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[*] posted on 7-7-2021 at 11:48


Divalent Mercury selenite and probably samarium selenite. I used samarium chloride and sodium selenate, when I added the required amount of sodium selenate it did not precipitated, so I added Na2SeO3 solution until it precipitate, does anyone have any idea what type of samarium selenite it might be. I have seen mixed rare earth selenites ( for example (NdxPr1−x(HSeO3)(SeO3)⋅2H2O)), but I do not know how it is in the case of sodium.

received_1401736546862268.jpeg - 235kB




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[*] posted on 7-7-2021 at 23:57


Mercury(II) selenite isn't white? It clearly has a somewhat yellow color in your vial. I have a few mercury(II) salts (Hg(CH3COO)2, HgCl2, Hg(SCN)2) and these are purely white. Mercury(II) anion is colorless. But of course, some combinations of colorless ions can lead to colored compounds, so the yellow color may be its real color and not due to some impurity.

I also wonder how your red selenium is looking now. Is it still red? I made some half a year ago or so, but now it is almost purely grey.





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[*] posted on 8-7-2021 at 05:25


Yes it has yellowish colour, i have too salts which you mentioned and i agree with you all of them are white. My mercury compounds are of good quality. Look at the photo on this link it has a really yellowish color.

https://onyxmet.com/index.php?route=product/product&prod...

My selenium was dark gray. A few weeks ago I made dioxide from selenium granules, I did not need that powder, so I dissolved it in nitric acid with the granules

[Edited on 8-7-2021 by vano]




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[*] posted on 10-7-2021 at 11:51



I made this crystal from mercury selenite, I melted it. I noticed that the mercury was produced, also the smell of selenium, not selenium dioxide. Could it be selenide? Or a mixture of selenite and selenide? I then heated more and got a dark opaque, hard crystal.

received_228260688734897.jpeg - 96kB




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[*] posted on 11-7-2021 at 05:53


This is the final product

received_2955512184696487.jpeg - 130kB




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[*] posted on 31-7-2021 at 02:37


Quote: Originally posted by vano  
Divalent Mercury selenite and probably samarium selenite. I used samarium chloride and sodium selenate, when I added the required amount of sodium selenate it did not precipitated, so I added Na2SeO3 solution until it precipitate, does anyone have any idea what type of samarium selenite it might be. I have seen mixed rare earth selenites ( for example (NdxPr1−x(HSeO3)(SeO3)⋅2H2O)), but I do not know how it is in the case of sodium.



Also this samarium selenite in vial is only 1.62 gram. It is very light.

[Edited on 31-7-2021 by vano]




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[*] posted on 2-8-2021 at 07:08


Also it can absorb UV light very very well.



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[*] posted on 10-4-2022 at 04:55


Hello! I made chromium selenite Cr2(SeO3)3 • ?H2O and cobalt selenate hexahydrate CoSeO4 • 6H2O

277360399_540124077717057_212278198369117374_n.jpg - 595kB

277467287_494214432424953_3777650052295792514_n.jpg - 505kB



[Edited on 10-4-2022 by vano]




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[*] posted on 10-4-2022 at 14:17


Oh, that cobalt selenate! I much appreciate your efforts to make selenium compounds, Vano. I stay away from them myself because of their toxicity.

Regarding the rare earths, I can only advise you to check a good book on RE compounds, because they oftentimes are more complicated than you would expect. Remember the violuric acid compounds, which may include other anions, as in the attachment posted here by diachrynic.
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[*] posted on 11-4-2022 at 10:20


Quote: Originally posted by Bezaleel  
Oh, that cobalt selenate! I much appreciate your efforts to make selenium compounds, Vano. I stay away from them myself because of their toxicity.

Regarding the rare earths, I can only advise you to check a good book on RE compounds, because they oftentimes are more complicated than you would expect. Remember the violuric acid compounds, which may include other anions, as in the attachment posted here by diachrynic.


thanks! yes i know what you mean about RE. i have some RE metals, maybe i will make some selenium salts from this metals. now i'm thinking to make sodium fluoroselenite. i found old book in laboratory. in this book there are good selenium compounds. also it's very easy to make.

SeO2 + NaF = NaSeO3F (at 250C)





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[*] posted on 12-4-2022 at 02:02


Hi. I made cobalt selenite again and also anhydrous selenite.

received_810980003638710.jpeg - 252kB
received_509556507414364.jpeg - 226kB
received_3249263298636231.jpeg - 170kB





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[*] posted on 12-4-2022 at 20:34


Gorgeous!!!



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[*] posted on 12-4-2022 at 21:07


Love the colors!
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[*] posted on 12-4-2022 at 22:03


Thanks!



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[*] posted on 26-4-2022 at 06:11


Today I made selenium tetrabromide from Amorphous selenium and bromine. Then I sublimated the compound.

9D69103F-FA2F-4D51-9617-914C4F99E7CE.jpeg - 1.8MB0A435E38-B911-4F70-947F-D07CF1608EBB.jpeg - 1.8MB




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[*] posted on 26-4-2022 at 11:39


it gets more dark. i made insoluble complex salt Cs2[SeBr6] from it.



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[*] posted on 28-4-2022 at 15:58


Quote: Originally posted by vano  
Hi. I made cobalt selenite again and also anhydrous selenite.

Wow, the colours!
Is the difference in colour compared to your first synthesis due to different lighting conditions when you took the photos, or is the result of your second synthesis really much deeper in colour that the first?

Quote: Originally posted by vano  
it gets more dark. i made insoluble complex salt Cs2[SeBr6] from it.

Does it have the same colour as your SeBr4?

If the SeBr4 turns lighter, it probably turns from its beta into its alpha form (Wiki).


[Edited on 29-4-2022 by Bezaleel]
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[*] posted on 28-4-2022 at 22:33


Hi Bezaleel!

1) I think it cause because of light. but also I think in my sodium selenite solution there was some carbonate impurity. I used to make sodium selenite from selenium. but now I have one jar of pure reagent.

also, cobalt selenite precipitation is a little bit hard than Cu and Ni selenites. I dissolved sodium selenite and cobalt chloride hydrates in hot water. then I mixed the solution but nothing precipitated, then I poured the mixture into another beaker and there was cold water. then it precipitated instantly. From my experience, you cant make the compound with a high yield just dissolve compounds in hot or cold water and mix them.

2)Yes they have similar colors. when it's dry I'll show you a photo.




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[*] posted on 30-4-2022 at 04:43


Selenium iodide Se2I2.

40688555-4119-4BC1-B928-F27DCAAD2E3B.jpeg - 2.5MB

3D71E81E-4ECA-4F66-86A1-4E4359CAE1FD.jpeg - 1.7MB

[Edited on 30-4-2022 by vano]




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