zephler1
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Thallium (I) Nitrate oxidation to Thallium (III) Nitrate?
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.
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BromicAcid
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If you react peroxide with thallium (I) nitrate (with a little bit of base) you will likely end up with
Tl<sub>2</sub>O<sub>3</sub>. Most of the Tl<sup>3+</sup> 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(NO<sub>3</sub> <sub>3</sub>*3H<sub>2</sub>O is prepared by dissolving thallium (III) oxide in cold nitric acid.<sup>42</sup>
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
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blogfast25
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I haven't peeked at the reduction potentials but I think:
NO<sub>3</sub><sup>-</sup> + 4 H<sup>+</sup> + 3 e<sup>-</sup> === > NO + 2
H<sub>2</sub>O
... 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]
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Bert
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Thread Moved
3-1-2015 at 07:10 |
BromicAcid
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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, TlNO<sub>3</sub>*3HNO<sub>3</sub>, 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, TlNO<sub>3</sub>*2HNO<sub>3</sub>. 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, 2TlNO<sub>3</sub>*Tl(NO<sub>3</sub><sub>3</sub>, 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(NO<sub>3</sub><sub>3</sub>*3H<sub>2</sub>O. 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.
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zephler1
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Thanks for the info - I have decided not to touch this one!
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nezza
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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.
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