Aqueous Transitional-Metal Chemistry

[Swany]

Transitional metals have many oxidation states, and many are colorful and unique. This is basically just a fun topic that discusses these.

 

I am preparing some FeCl2 solution, which is a green color. If you let it stand stoppered (or else it will oxidise to form a orange FeCl3), you will get a very neat crystal of FeCl2 which will oxidise when you take it out, but its really neat. Since I am not growing crystals, rather magnetite, I will divide the stock solution, and allow half of it to oxidise to FeCl3. This will be mixed with the FeCl2. I will then add ammonia to precipitate FeO.Fe2O3(magnetite). I could go on to make some ferrofluid, but thats another day. So thats something kinda neat.

 

I am in the process of dissolving some Ti flakes, assumed to be pure, in some HCl to hopefully produce a blue Ti (III) chloride solution. However, when first added, it turned a bit green. I shook this around for about 10 min, and it kept dissolving very slowly, with a small amount of H2 production. Then, it turned CLEAR instantly. This was a shock, as it was stoppered, and clear indicates Ti (IV). Not what I wanted, so then after some time in a hot water bath, which greatly sped up the reaction, so it was producing lots of bubbles to make it actually appear to double in volume, it now appears to be a black solution. This solution is not a solution tohugh, as if you slosh it on the walls of the tube, it remains clear. So it is not very conc. TiCl3, as it would be blue, though it shows some blueness sometimes. It appears to just be a black suspension.

 

I now question my HCl purity, though it should be decent. It was from a hardware store... I will check it out in the morning. Pictures may come, as this is mildly amusing.

[Mumbles]

I think you could like my inorganic class. That is a large portion of what we do. Just FYI, the Iron (III) ion is not specifically orange. I think it may be blue actually. It is actually a complex ion formed by hydrolysing. I can't think of the formula off the top of my head.

 

Give Mangansese a try sometime. It gives a ton of different colors. Don't forget to try the uncommon oxidation states as well. There is the ferrate ion still to be had of course(+6 I think).

[Swany]

It (Ti) has mostly dissolved, and now it seems to be a dark purple/blue solution. This matches the MSDS namings, and it is quite concetrated, so all makes sense.

[somebody]

Fe has 5 different oxidation states, 1+, 2+, 3+, 4+ and 6+.

I might do some experiments with them soon

[Swany]

I now have some TiCl3 solution and lots(500mls) of FeCl2 solution. Any suggestions, or requests for expiremintation are welcome. Hopefully I can play with these later...

[Swany]

I have been playing with some chromium states for the past 30 minutes.

 

Starting with ammonium dichromate in the +6 oxidation state. The rather amusing decomposition of this creates large piles of Cr2O3, H2O, and N2. My initial goal was to make some CrO3, or 'chromic acid'. I attempted this with H2O2 at 27%, and simply placed a spatula of Cr2O3 from the decomposition in the H2O2. It fizzed gently, and I noticed that it turned purplish in some spots. CrO3 solution is red. I added some ammonium dichromate to H2O2, and it turned purple. I guess it didn't decompose all of the way.

 

Unfortunately this reaction was knocked off of my counter. That solution happned to be carcigenic, and it burned/bleached my skin nicely.

 

Not to be dissuaded, I added a big old spoonful of this to 20mls of the 27% H2O2. It started fizzing. Lots. Oh shit, its fuming... I take a wary sniff, ok just water, I think. As expected. Then I touched the side of the beaker, hmm very hot. At this point it started hissing and turned into a fountain of billows of steam. When it was all done, a paste of the Cr2O3 was left. I added 150mls of 3% H2O2. It didn't explode, so I'll check on it later. I shall expirement some more!

 

EDIT: Moving on, the stuff that I added the 3% to was about done bubbling, so I added a bit more 27%, and it turned a darker color, as it was a light drab olive color and the Cr2O3 was still floating around. This bubbling solution added to NaOH and NH3 soln. turned a solid yellow color, no precipitate. This seems to be the diagnosis with an acidic enviroment... I should really see what acid does, but I dont want to go to the lab. Best it may get is lemon juice or vinegar...

 

Im addicted to this! Very mysterious and quite cool. Mn is up next.

[Rooster]

The chromic acid crystals I have seen(not in solution), were purpleish red. Darker red than your avatar, Swany. The MSDS says "Odorless red to dark purple crystals or powder". So don't worry if your solution is dark red or purpleish.

 

Please get some pics! It freshens the thread up a lot. I wish people would post more pics and vids, the documentation is just as cool, if not cooler than the text.

[Swany]

I shall do some expirementation, but it will all be video, as my camera is in a large city for a week. Tragic, but, I shall prevail.

 

I am going to document the whole chromium process tonight.

 

The MnO2 dissolved in the HCl over a day to form a yellow solution.

[Swany]

Pictures of the iron chloride oxidation with H2O2.