morsagh - 17-1-2017 at 08:45
So today i tried to prepare sodium cuprate(III). I heated mixture of 0,5g sodium peroxide and 0,5g copper(II) oxide. Mixture melted and than quickly
solidified. When product was put directly in flame, orange solid is produced. Product is not very soluble in water, and violently reacts with diluted
sulfuric acid while lot of gas is produced. Do you think this blue/black solid can be sodium cuprate?
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[Edited on 17-1-2017 by morsagh]
[Edited on 17-1-2017 by morsagh]
AJKOER - 18-1-2017 at 19:49
Per Wikipedia on Cuprate (https://en.m.wikipedia.org/wiki/Cuprate ):
"This dark blue diamagnetic solid is produced by heating potassium peroxide and copper(II) oxide in an atmosphere of oxygen:[2]
K2O2 + 2 CuO → 2 KCuO2 "
Also, per Wikipedia on K2O2 (https://en.m.wikipedia.org/wiki/Potassium_peroxide ):
"Potassium peroxide reacts with water to form potassium hydroxide and oxygen:
2 K2O2 + 2 H2O → 4 KOH + O2 "
Assuming similar chemistry for sodium salts, my concerns would be to relating to the presence of water vapor and heating in an oxygen rich atmosphere.
Tsjerk - 18-1-2017 at 23:42
Oxygen would be enriched by heating peroxide salt in a tube and water would be driven of by the same heat. I would say you might have succeeded; can
you think of any other tests to confirm it is cuprate?
[Edited on 19-1-2017 by Tsjerk]
DFliyerz - 19-1-2017 at 10:12
Perhaps try dissolving it in water? I remember making a cuprate solution by electrolysing a sodium hydroxide solution with a copper anode, and it was
a very dark blue color.
morsagh - 19-1-2017 at 12:06
Product of electrolysis is Na2Cu(OH)4, not cuprate with Cu(III). Any other ideas?
ave369 - 19-1-2017 at 13:18
By the way, can you make Cu2O3 with persulfate as oxidizer? I tried ammonium persulfate on Cu(OH)2, but I forgot about the alkali (NaOH) that was used
to precipitate Cu(OH)2. It reacted with the ammonium salt, and the resulting ammonia gave the characteristic deep blue color of the ammino copper (II)
complex.
Should I try this with potassium persulfate? I've got loads of the ammonium persulfate but little of the potassium salt.
AJKOER - 20-1-2017 at 05:30
A short prior thread on the topic at http://www.sciencemadness.org/talk/viewthread.php?tid=64346 .
morsagh - 20-1-2017 at 07:08
We are talking about Cu(III) cuprate not Cu(II) like Na2Cu(OH)4.