Sciencemadness Discussion Board - Thallium (I) Nitrate oxidation to Thallium (III) Nitrate?

Thallium (I) Nitrate oxidation to Thallium (III) Nitrate?

zephler1 - 2-1-2015 at 13:47

I can't seem to find any references on this - can someone help?

I was thinking that a simple treatment for say 8 hours in 60C H2O2 would do the trick - does anyone have experience with Thallium salts? Yes I know they are incredibly toxic.

BromicAcid - 2-1-2015 at 17:22

If you react peroxide with thallium (I) nitrate (with a little bit of base) you will likely end up with Tl2O3. Most of the Tl3+ compounds are easily hydrolyzed and at these temps that is what you will be doing. However, Tl (III) compounds are usually prepared starting from the thallium (III) oxide so you would have your starting material.

Quote:

Thallium (III) nitrate Tl(NO3

3*3H2O is prepared by dissolving thallium (III) oxide in cold nitric acid.42 It is readily hydrolyzed to thallium (III) oxide, and loses nitric acid on exposure to air.

(42) J.W. Mellor, A Comprehensive Treatise on Inorganic and Theoretical Chemistry, Vol. 5, Longmans (1924)

Above quote is from:

A.G. Lee, The Chemistry of Thallium, Elsevier Publishing Company (1971)

I believe we have that volume of Mellor's work in the library so that would be a good place to start. However, according to the literature, it looks like you should be able to perform the transformation from thallium (I) nitrate to thallium (III) nitrate using dinitrogen pentoxide

blogfast25 - 3-1-2015 at 05:41

I haven't peeked at the reduction potentials but I think:

NO3- + 4 H+ + 3 e- === > NO + 2 H2O

... i.e. nitric acid itself, should be able to kick Tl from (I) to (III). Fairly strong nitric acid and simmering should cause this oxidation to take place.

[Edited on 3-1-2015 by blogfast25]

BromicAcid - 3-1-2015 at 09:09

Some information from the Mellor reference above:

Quote:

E. Carstanj en found that thallium is more readily attacked by nitric acid than by the other mineral acids, and with
dil. nitric acid, hydrogen is evolved. W. Crookes showed that thallous nitrate is the main product, but if an excess of cone, nitric acid is used, much thallic nitrate is formed;

Quote:

Ditte assumed that in aq. soln., nitric acid forms a complex thallous trihydronitrate, TlNO3*3HNO3, but it could not be isolated ; H. L. Wells and F. J. Metzger saturated nitric acid, sp. gr. 1*5, with thallous nitrate, and at 0°, obtained crystals of thallous dihydronitrate, TlNO3*2HNO3. The salt loses nitric acid rapidly on exposure to air. If the thallous nitrate be dissolved in hot nitric acid of sp. gr. 1.5, H. L. Wells and F. J. Metzger found some thallic nitrate is formed, for the soln. deposits colourless prismatic crystals of thallosic nitrate, 2TlNO3*Tl(NO3

3, which are stable in dry air, but rapidly blacken in moist air.

Quote:

J. E. Willm, A. Strecker, and R. J. Meyer dissolved thallic oxide or hydroxide in nitric acid of sp. gr. 1.4, and found that the conc. soln. deposited colourless deliquescent crystals of thallic nitrate, Tl(NO3

3*3H2O. C. F. Rammelsberg said that the crystals are rhombohedral. The salt is hydrolyzed in the presence of much water and thallic oxide is formed; it is also decomposed, according to J. E. Willm, if heated even below 100°. When exposed to air, the crystals lose nitric acid.

Thallium chemistry can be tricky, also until reading through the specific references I didn't realize how much covalent character the thallic salts have, with their marked toxicity it's a horrible fact that they like to sublime readily. The notes above are just the highlights, your best bet would be to read the Mellor reference in its entirety.

zephler1 - 3-1-2015 at 18:10

Thanks for the info - I have decided not to touch this one!

nezza - 4-1-2015 at 02:37

My route would be :-

1. Make solution strongly alkaline. (Thallous hydroxide and carbonate are soluble).
2. Add hydrogen peroxide. This should precipitate thallic oxide/hydroxide.
3. Filter, wash and dissolve precipitate in dilute nitric acid.

Of course bear in mind that all soluble thallium salts are highly toxic and many are absorbed through the skin.