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Pok
potassium Prometheus
Posts: 176
Registered: 5-12-2010
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I also found this claim. But how should it work? It's substractive colours, not additive. This means that the absorption of Er and Tm is added. So
erbium can't make the greenish Tm colour weaker or even "colourless". I think it is a mistake in the article or an imprecise description.
@blogfast: I don't see a barrage of exclamation marks. And no: it's not established that it is thulium! There are 2 weak hints (magnetic and pale
green) but no positive proof! The metal could also be 50 % Tm and 50 % xxx (with colourless ions) or even 0 % Tm, 1 % x (with green ions) and 99 % y
(with colourless ions).
[Edited on 9-7-2014 by Pok]
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IrC
International Hazard
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He said he bought a 1 gm sample from Metallium. They have 99% Thulium. I have done business with David Hamric for over a decade. A more honest
conscientious seller I have never found. If he says it's 99% Thulium then that is what it is. He can also provide assay information upon request.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Brain&Force
Hazard to Lanthanides
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I can definitely corroborate IrC's statement - Metallium even offered to help me out when I suspected contamination issues with my terbium sample.
Have you tried a density test? That can help us weed out any issues. (Just make sure to use oil rather than water - thulium will slowly react with the
water.)
At the end of the day, simulating atoms doesn't beat working with the real things...
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Pok
potassium Prometheus
Posts: 176
Registered: 5-12-2010
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He bought the first sample from another supplier. I also believe that it is thulium. But "belief" is not a postive proof. And in the case of
metallium, neither a CoA nor the reputation of a seller is a proof.
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kmno4
International Hazard
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I think it works in similar way like in case of Co(II) + Ni solutions: at some ratio solution becomes nearly colourless.
Er absorbs "green ligth", Tm absorbs "pink light", total effect depends on Er/Tm ratio (and source of ligt).
It is very similar situation to Nd-Pr pair - colour of n electron on 4f orbital is similar to 14-n configuration (Pr, Tm are green, Nd, Er are pink).
Some time ago I was playing with Nd-Pr mixtures: Nd/Pr oxalate was pale green under fluorescent lamp and pale pink under daylight.
The same situation was in solutions and it seems that at some Nd/Pr ratio solution would be coloureless.
However, Nd has larger molar absorbance coefficient in visible spectrum (let's say it is 10) than Tm does (let's say it is 2,5)
But this "colourless" is oversimplification, as Pok noticed: when some bands dissapear, the rest cannot be strictly colourless !
Human eyes interpret it as "darker", without any particular colours.
Without spectroscopy it is hard to say anything concrete....
Слава Україні !
Героям слава !
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sbreheny
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Pok is correct - my original sample is from a different seller. I bought an additional sample from Metalium to compare against but I have not tried
doing any chemical reactions on the second sample - only appearance and magnetic tests.
Quote: Originally posted by Pok  | | He bought the first sample from another supplier. I also believe that it is thulium. But "belief" is not a postive proof. And in the case of
metallium, neither a CoA nor the reputation of a seller is a proof. |
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