Brain&Force
Hazard to Lanthanides
Posts: 1302
Registered: 13-11-2013
Location: UW-Madison
Member Is Offline
Mood: Incommensurately modulated
|
|
Transient formation of ytterbium(II) in aqueous solution?
As I have no glassware or other lab equipment at home, everything I do is estimation unless otherwise specified.
I tore a small bit of ytterbium metal off my main chunk and dissolved it in an aqueous solution citric acid. (Yes, I should have some other acid on
hand.) It began dissolving instantly, and the solution quickly turned yellow.
From what I have read nearly all ytterbium(III) salts are colorless, so I was surprised to see that the solution turned yellowish! The color stayed
the same in both sunlight and fluorescent light.
After about 15 minutes, the ytterbium piece was still dissolving, but the solution had faded considerably, and it turned colorless (in all types of
lighting) within the hour.
I can only think of two explanations for the color: either a diaquabis/tris(citrato)ytterbate(III) complex has formed and was destroyed by the
continued addition of ytterbium, or a relatively stable ytterbium(II) intermediate has formed and oxidized to ytterbium(III). Considering that
ytterbium(II) has a favorable 4f14 electron configuration I wouldn't be surprised if the latter was the case.
Also, samarium sometimes exhibits a similar reaction when added to acid - a blood red samarium(II) intermediate has formed. I've added samarium to
citric but this didn't happen at all.
At the end of the day, simulating atoms doesn't beat working with the real things...
|
|
|
Chemosynthesis
International Hazard
Posts: 1071
Registered: 26-9-2013
Member Is Offline
Mood: No Mood
|
|
Interesting. I also find it fascinating you don't have any lab equipment at home. I am very impressed by that alone.
I also agree with your reasoning as to likelihood of the latter occurring due to 18 electron 'rule' stability. Could you cut the samarium under the
citric acid solution to try to mitigate oxidation and see if that coaxes a reaction, or did you recently manipulate it in any manner to expose a fresh
face to the acid?
|
|
|
Brain&Force
Hazard to Lanthanides
Posts: 1302
Registered: 13-11-2013
Location: UW-Madison
Member Is Offline
Mood: Incommensurately modulated
|
|
Quote: Originally posted by Chemosynthesis  | Interesting. I also find it fascinating you don't have any lab equipment at home. I am very impressed by that alone.
I also agree with your reasoning as to likelihood of the latter occurring due to 18 electron 'rule' stability. Could you cut the samarium under the
citric acid solution to try to mitigate oxidation and see if that coaxes a reaction, or did you recently manipulate it in any manner to expose a fresh
face to the acid? |
I guess it's the 32 electron rule? (That seems like way too much though!)
I might try the Sm + citric acid reaction later, I can file a piece down and test it again. blogfast25 has tried the reaction though, with no success.
At the end of the day, simulating atoms doesn't beat working with the real things...
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
