Sciencemadness Discussion Board

Lanthanides?

DraconicAcid - 30-11-2021 at 21:01

So I'm looking at lanthanides on AliExpress. Some of them are surprisingly cheap.

Holmium- 20 g for $30.
Ytterbium- 20 g for $24
Samarium- 100g for $24
Erbium- 20 g for $30
Gadolinium- 50g for $40.
Dysprosium 10g for $30.

Any of these do particularly interesting chemistry? I'm mostly into coordination chemistry.

Bedlasky - 1-12-2021 at 00:01

Samarium and ytterbium have interesting chemistry in divalent state. SmI2 and YbI2 can be made from metal and iodine in THF. Both are used in several organic reductions. Sm(II) is more reactive than Yb(II) due to less stable configuration.

https://sci-hub.se/https://pubs.acs.org/doi/10.1021/ja00528a...

https://en.wikipedia.org/wiki/Reductions_with_samarium(II)_i...

https://books.google.cz/books?id=QUfQamGsEgwC&printsec=f...

Eu(II) is stable even in aqueous solution. It can photochemicaly reduce water to hydrogen. But europium is expensive.

Lanthanides in III oxidation state have very similar chemistry. You can try complexes in different acids like HClO4, HNO3, H2SO4, HCl, HBr etc. Each solution should have different shade of colour, I tried this with neodymium. Gadolinium(III) forms colourless solutions, so not much spectacular aqueous chemistry. However metallic gadolinium is ferromagnetic below 20°C.

Cerium, praseodymium and terbium have interesting chemistry in IV oxidation state. Ce(IV) have very rich chemistry, Pr(IV) and Tb(IV) not so much, they form periodate, tellurate and polytungstate complexes in aqueous solution. Terbium is expensive, but cerium and praseodymium can be obtained quite cheap.

nezza - 3-12-2021 at 07:39

Gadolinium has some interesting magnetic properties. At room temperature it is strongly paramegnic (weakly attracted to a magnet), but below 20 deg C it becomes ferromagnetic and is strongly attracted to magnets. Erbium anf Holmium salts have interesting colour changes under different lighting conditions (Fluorescent vs daylight).

[Edited on 3-12-2021 by nezza]

DraconicAcid - 3-12-2021 at 16:44

Well, I went for the samarium. Now to see if I ever get around to doing anything with it.

Fery - 3-12-2021 at 23:13

DraconicAcid - Sm metal dissolves easily in acids into Sm(III) salts. If you would like Sm(II) you can react Sm + CH2I2. You can obtain diiodomethane by Finkelstein reaction from dichloromethane + NaI in acetone environment.
I do not know how much pure lanthanides are sold in AliExpress. I used to buy lanthanides always from onyxmet.pl and chemcraft.su

[Edited on 4-12-2021 by Fery]

DraconicAcid - 3-12-2021 at 23:57

Thanks- I might have to try that (I've also found a prep for SmI2 using iodine and THF, but I don't have the latter ether- just diethyl. I may be getting some glyme later on, but not sure if that will work).

Bedlasky - 4-12-2021 at 00:45

I think that glyme should work. Book which I mentioned above mention SmI2 complexes with diglyme and diethyleneglycol. It also mention preparation in different solvents than THF, including such a common solvents like acetonitrile, isopropyl alcohol or tert-butyl alcohol.



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[Edited on 4-12-2021 by Bedlasky]