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 Post subject: Re: Нуждаюсь в совете
PostPosted: 02 Oct 2022 08:30 
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thank you. I dissolved some cobalt selenite dihydrate in sulfamic acid, very easily soluble. I'm trying to make some crystals.


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 04 Oct 2022 16:42 
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Hello! I have a question about arsenic. I have good ores of arsenic, I have orpiment. I made some powder from a few ores with a mortar and pestle. almost all were As2S3, I couldn't powderize just silicate rocks, they were hard, so then I separate them with tweezers. I want to make any arsenic compound or arsenic, but I want it in a beaker. now I can't make steel apparatus and distilled arsenic from sulfide iron mixture. I added conc. hydrochloric acid but sulfide didn't dissolve in it. what can I do?


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 04 Oct 2022 16:44 
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once I made amorphous antimony from its trichloride acidic solution, I reduced it with zinc powder, I'm thinking maybe I can same with arsenic.


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 04 Oct 2022 17:28 
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I dissolved it in conc. nitric acid, I just thought that I don't have it but I found a few mls. ill buy the acid and make more H3AsO4 solution. I'll take any advice on what to do then with arsenic acid.


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 04 Oct 2022 20:42 
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Sulfuric acid also forms.
As2S3 + 28 HNO3 → 2 H3AsO4 + 3 H2SO4 + 28 NO2 + 8 H2O
I think you should precipitate MgNH4AsO4 to separate AsO4(3-)

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 Post subject: Re: Нуждаюсь в совете
PostPosted: 04 Oct 2022 22:37 
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thanks, Volodymyr!

I read that sulfuric acid is also useful for this reaction, but I use 96% sulfuric acid, nothing happened, and no SO2 smell also of course. then I dilute it but also nothing happened.

good idea for separating 3&5 valency of arsenic, but if I use exec conc. nitric acid must form only arsenic(VI), isn't it?


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 05 Oct 2022 10:08 
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I said about another.
Nitric acid reacts with As2S3 and gives mixture of arsenic acid and sulfuric acid. If sulfuric acid does not interfere it is OK.

If necessary, sulfate SO42- and arsenate AsO43- can be separated by precipitating of MgNH4AsO4.
(AsO43- is As(V))
______
You are right - nitric acid oxidizes As(III) to As(V).

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 Post subject: Re: Нуждаюсь в совете
PostPosted: 05 Oct 2022 17:41 
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thank you!


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 11 Oct 2022 21:21 
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Volodymyr I made MgNH4AsO4 as you advised me. so I separate it from the sulfate. what is the best next step what do you think? if I add nitric acid and then add sodium carbonate to neutralize it, it must precipitate MgNH4AsO4 again, isn't it? because there are Mg&NH4 and sodium arsenate that won't crystalize.


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 12 Oct 2022 10:46 
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1. MgNH4AsO4*6H2O is used in gravimetric analysis of arsenic. It is the weight form. I think this compound could add to your collection on its own.

2. I would try this:

MgNH4AsO4 + NaOH (solution) = Na3AsO4 + Mg(OH)2 + NH3 + H2O
Filtrate Mg(OH)2.
Na3AsO4 and NH3 are in the solution.
Boil the solution to evaporate NH3

3. A small amount of MgNH4AsO4 + organic compound. Heat in test-tube to obtain As in the wall of test-tube. Similar to viewtopic.php?p=140008#p140008
Quote:
Подобный опыт (получение зеркала мышьяка, возгонка и окисление) легко и безопасно сделать в небольшом масштабе:
в тонкую трубочку (на фото кварцевая, получается и со стеклянной) вносится с горошину по объему арсеназо III, придавливается комочком кварцевой ваты (стеклянная тоже должна подойти), и верх тоже закрывается комочком.
Греют сначала осторожно, чтобы разложить арсеназо (на открытом воздухе!) - появляются капли воды, их нужно "согнать", слабо прогрев верх.
Как трубка остыла у нас получилась смесь угля (с избытком) и оксида мышьяка.
Если теперь дно прогреть посильнее - возгоняется зеркало мышьяка, которое вверху частично окисляется.
Прилегающая к стеклу пленка мышьяка блестит.

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 Post subject: Re: Нуждаюсь в совете
PostPosted: 12 Oct 2022 18:37 
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thank you! that's interesting.

photo of magnesium-ammonium arsenate hydrate.


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 16:49 
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hello! I have ferrocene, I want to make some cyclopentadiene to make other metal complexes, how can I make it?


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 18:36 
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Unfortunately this aim is approximately equal to obtaining of ethylene from polyethylene. Theoretically it is possible but practically - not.

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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 20:39 
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wow, I didn't think that this reaction is such hard. so what can I make from it what do you think?


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 21:18 
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This complex is enough stable. I think, that to use ferrocene for obtaining of cyclopentadiene is not a good idea.

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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 21:22 
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maybe acetylation and such reactions are better for practicing. I just requested a few hundred grams from the university warehouse, so I must use it for something.


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 21:29 
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For example, vacuum sublimation (purification).

More serious things are the reactions of substitution in the cyclopentadiene ring
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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 21:32 
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Thermal Decomposition of Ferrocene as a Method for Production of Single-Walled Carbon Nanotubes without Additional Carbon Sources // J. Phys. Chem. B 2006, 110, 42, 20973–20977
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 Post subject: Re: Нуждаюсь в совете
PostPosted: 17 Oct 2022 22:39 
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thank you! sublimation was first what I thought when I lost hope to make cyclopentadiene :). working on a cyclopentadiene ring looks interesting. i think ill try acetylation.


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 Post subject: Re: Нуждаюсь в совете
PostPosted: 23 Oct 2022 12:00 
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Всем привет, сегодня вспомнил о старой банке в которую сливались ненужные остатки этилового спирта и обнаружыл в ней кристаллы.
Разве для образования крислов не нужно большой концентрации соли? И есть идеи какая могла быть соль в спирте?
Спасибо!
Фото 1
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Фото 2
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p.s. я не химик :)


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