То есть его можно спокойно держать в руках без вреда?

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.

Ammonium trichromate - (NH4)2Cr3O10.

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.

I have never researched this topic. and what is it?

I know about it. but I never understand what is different.

Old conception:
1) Zn + 2H⁺ = Zn²⁺ +2H
2) Mo(VI) + H = Mo(V) + H⁺

New conception:
Zn + 2Mo(VI) = 2Mo(V) + Zn²⁺

so its zinc issue not hydrogen?

The reducing agent is zinc (or other metals), not hydrogen.

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.

Compounds of Mo(III) may be green.

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?

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.

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?

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).

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

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.