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.
•This is a barium selenide. It has very beautiful colour, i have much more in ampoule, but not here.
•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.
•This is cadmium polyselenide, just a fact it changed colour and get darker. Above is a link to compare.
•And boring Pb and Ni Selenides.
This is part of the selenium compounds which I found this time.
[Edited on 23-3-2021 by vano]vano - 23-3-2021 at 04:44
Just nice photo of Selenites.
Metallophile - 23-3-2021 at 16:14
Very nice! I always click on your posts, to see what new colors you've come up with. vano - 23-3-2021 at 23:10
Thanks!woelen - 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).vano - 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.vano - 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.
woelen - 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.
vano - 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.
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]vano - 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.
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]vano - 2-8-2021 at 07:08
Also it can absorb UV light very very well.vano - 10-4-2022 at 04:55
Hello! I made chromium selenite Cr2(SeO3)3 • ?H2O and cobalt selenate hexahydrate CoSeO4 • 6H2O
[Edited on 10-4-2022 by vano]Bezaleel - 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.vano - 11-4-2022 at 10:20
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)
vano - 12-4-2022 at 02:02
Hi. I made cobalt selenite again and also anhydrous selenite.
DraconicAcid - 12-4-2022 at 20:34
Gorgeous!!!Lion850 - 12-4-2022 at 21:07
Love the colors!vano - 12-4-2022 at 22:03
Thanks!vano - 26-4-2022 at 06:11
Today I made selenium tetrabromide from Amorphous selenium and bromine. Then I sublimated the compound.
vano - 26-4-2022 at 11:39
it gets more dark. i made insoluble complex salt Cs2[SeBr6] from it.Bezaleel - 28-4-2022 at 15:58
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?
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]vano - 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.vano - 30-4-2022 at 04:43
Selenium iodide Se2I2.
[Edited on 30-4-2022 by vano]MrHomeScientist - 1-6-2022 at 06:36
Hi. I made cobalt selenite again and also anhydrous selenite.
Those are spectacular colors! How did you make them? Do you have a procedure posted in another thread? I'd like to try this myself.vano - 1-6-2022 at 07:18
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.
Hi. this is the procedure.vano - 1-6-2022 at 07:19
Selenium dioxide.
vano - 9-6-2022 at 11:26
Caesium hexabromoselenite.
TITANIUM SELENITE(?)
vano - 21-9-2022 at 07:01
We know that many compounds of Ti(III) are unstable, for example hydroxide, tungstate... but yesterday i mix some titanium trichloride and sodium
selenite solutions, it is logical to think that titanium can reduce selenite to red selenium in the solution. but when I tried this reaction in a test
tube it wasn't red allotropy.
i made more, then i filtered it and put on petri dish, i can dry it with other methods, but i use sunlight, because if there was any red selenium or
it was red selenium precipitate it must turn black color. onced i tryed to dry red alotropy under sunlight and it takes 30 minute to be black.
unfortunately i couldn't find any info about trivalent selenite.
woelen - 22-9-2022 at 00:28
Maybe the reduction by titanium(III) is so vigorous, that the selenium is reduced all the way down to selenide. That would lead to TiSe2. I don't know
the properties of that.vano - 22-9-2022 at 05:37
I'm not sure 100% about what it is, These are just my assumptions. bad thing is that I couldn't find any info. so ill put all of my powder in nitric
acid and make some titanium dioxide hydrate. I have TiO2 but you know it's very inert, because of its calcinated temperature. and ill make some Ti(IV)
complexes, just more logical valency to work with.clearly_not_atara - 22-9-2022 at 05:50
Selenides of titanium may be alloy-like, TiSex, rather than salt-like. Selenium is not terribly electronegative. TiS2 is a conductor IIRC. vano - 22-9-2022 at 06:18
yes, many possible formulas, selenide, polyselenide, selenite, and different valency of titanium... unfortunately I can't make an analysis now. but
worth to try I think, but I don't recommend it for forum members. I just hate when I have chemical and I don't know exactly what it is. thanks,
everyone for your ideas!
