Ammonium trichromate - (NH4)2Cr3O10.
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| Хром, Молибден, Вольфрам и их соединения http://www.chemistry-chemists.com/forum/viewtopic.php?f=1&t=1112 |
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| Author: | Артем V [ 15 May 2022 14:18 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
Volodymyr wrote: Попадание внутрь, вдыхание аэрозоля или паров хромового ангидрида. То есть его можно спокойно держать в руках без вреда? |
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| Author: | Volodymyr [ 15 May 2022 15:27 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
Контакт с кожей не допускается. К другим реактивам это тоже относится. |
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| Author: | Юрий Денисов [ 15 May 2022 15:41 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
Volodymyr wrote: Контакт с кожей не допускается. К другим реактивам это тоже относится. Как нам сказали на лекции: "да бензол немного канцерогенен, но мы руки в нем мыли и ничего не случилось" Так и здесь - если попадет на руки смыть и не париться. |
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| Author: | vano34 [ 21 Jun 2022 11:52 ] | ||
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения | ||
Ammonium trichromate - (NH4)2Cr3O10.
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| Author: | vano34 [ 07 Jul 2022 14:49 ] | ||
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения | ||
kind of molybdenum blue. made from reducing MoO3 with atomic hydrogen. contains for example Mo8O23·xH2O Mo4O11·xH2O.
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| Author: | Volodymyr [ 07 Jul 2022 22:17 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
vano34 wrote: kind of molybdenum blue. made from reducing MoO3 with atomic hydrogen. contains for example Mo8O23·xH2O Mo4O11·xH2O. Now it is believed that the reducing agent is the surface of the metal (for example, zinc), not atomic hydrogen. |
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| Author: | vano34 [ 08 Jul 2022 09:13 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
I have never researched this topic. and what is it? |
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| Author: | Volodymyr [ 08 Jul 2022 09:26 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
https://en.wikipedia.org/wiki/Nascent_hydrogen |
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| Author: | vano34 [ 08 Jul 2022 11:53 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
I know about it. but I never understand what is different. |
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| Author: | Volodymyr [ 08 Jul 2022 12:09 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
Old conception: 1) Zn + 2H+ = Zn2+ +2H 2) Mo(VI) + H = Mo(V) + H+ New conception: Zn + 2Mo(VI) = 2Mo(V) + Zn2+ |
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| Author: | vano34 [ 09 Jul 2022 09:23 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
so its zinc issue not hydrogen? |
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| Author: | Volodymyr [ 09 Jul 2022 11:20 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
The reducing agent is zinc (or other metals), not hydrogen. |
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| Author: | vano34 [ 21 Jul 2022 21:49 ] | |||
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения | |||
Hello! weeks ago I made molybdenum metal from trioxide thermite. I washed the metal with hydrochloric acid, there was some aluminum. then maybe a week ago I made powder from larger pieces. it was easy to crack them. when I made powder again I washed it with hydrochloric acid. I am just interested in the valence of molybdenum in this green solution. it's hard to see the color in a beaker because it's opaque, it has a very dark green almost black color. the second photo is just this molybdenum, I just added a few drops of 1,10-phenanthroline solution and made a complex.
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| Author: | Volodymyr [ 21 Jul 2022 22:36 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
vano34 wrote: I am just interested in the valence of molybdenum in this green solution. Compounds of Mo(III) may be green. |
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| Author: | vano34 [ 21 Jul 2022 23:23 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
thank! I have never worked with trivalent molybdenum, I always thought that it is hard to make solid trivalent salt. what do you think can I make any trivalent salt easily? |
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| Author: | Volodymyr [ 22 Jul 2022 11:57 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
I think that it will not be possible to precipitate threevalent molybdenum salts from an aqueous solution. Threevalent molybdenum is a very good reduction agent. |
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| Author: | vano34 [ 22 Jul 2022 12:04 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
Yes, I thought that. it's very hard. Today I made a more concentrated solution of the phenanthroline complex. a small amount of dark red powder precipitate. do you think maybe it is a trivalent complex? |
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| Author: | Volodymyr [ 22 Jul 2022 12:30 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
It's possible, but I don't think so. Most likely red powder is Mo(V) or Mo(VI) complexes. I read a monograph on the analytical chemistry of molybdenum. There was no information about Mo(III)-complexes with phenanthroline in the book (in russian language http://chemistry-chemists.com/book5/him ... ov/Mo.djvu). |
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| Author: | Volodymyr [ 22 Jul 2022 12:40 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
I was wrong: Extractive spectrophotometry of the molybdenum (III) 1,10-phenanthroline thiocyanate and 2,2'-bipyridyl thiocyanate complexes // Talanta. 1973 Mar;20(3):342-6 Attachment:
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| Author: | vano34 [ 22 Jul 2022 12:43 ] |
| Post subject: | Re: Хром, Молибден, Вольфрам и их соединения |
thanks! I also dissolved molybdenum powder in an HF-HNO3 mixture, the solution was dark pink, I've never seen molybdenum with this color in the solution. very strange and also interesting element. I'm just thinking about molybdenum III in heteropolymetalate, I mean as heterometal not in polyoxometalate anion, like cobalt III. I've read that polyoxometalates can stabilize heterometal in an unstable oxidation state, for example, Nickel IV. unfortunately very poor information. I have old soviet books, the best inorganic books, but it's also hard to find such information here. thanks for the research! As far as I can see you are finding good researches, do you have any tips? I personally use sci-hub, but it's still difficult to get the information I need. |
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