morsagh
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Cuprites
I quote (translated from czech to english by me) from book "Lekářská chemie anorganická" by Prof. Antonín Hamsík: " copper(II) hydroxide can be
dissolved in strong base like sodium hydroxide to produce unstable cuprites for example Na2CuO2." Anybody have tried? Or some
other references (i didn´t find anything on internet)?
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MolecularWorld
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If it's anything like making ferrates or manganates, it probably requires molten hydroxides. At the temperature required to melt
sodium hydroxide, copper(II) hydroxide would instantly decompose to give cupric oxide, before (possibly) reacting with the molten lye.
Copper hydroxide, sodium hydroxide, and hydrogen peroxide may react in solution to form an unstable green compound, though when I tried to replicate this, it just turned black (cupric oxide).
Here's a mention of KCuO2. From the same page: "The light blue solid sodium tetrahydroxycuprate is well known, it is prepared by heating cupric hydroxide
with concentrated sodium hydroxide."
[Edited on 14-11-2015 by MolecularWorld]
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Texium
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I've made sodium cuprate before, by reacting copper(II) oxide with molten sodium hydroxide and then dissolving that in a concentrated sodium hydroxide
solution. It's dark blue in color. It was part of my Copper Carnival entry, which you can see here. (11th compound in the writeup)
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Amos
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Small amounts of cuprate can be made just by reacting copper hydroxide or basic copper carbonate with a hot solution of sodium hydroxide or even
sodium carbonate. If you're trying to isolate it, the best way to produce a workable quantity, if it's even possible, would be copper(II) oxide in
molten sodium hydroxide.
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The Volatile Chemist
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I always forget Tim's username (His subtitle is 'post harlot', and his username is a guitar pedal. He's made this before, and has a small bit about it
on his website.
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Texium
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Quote: Originally posted by The Volatile Chemist  | | I always forget Tim's username (His subtitle is 'post harlot', and his username is a guitar pedal. He's made this before, and has a small bit about it
on his website. |
12AX7
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AJKOER
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Per Wikipedia on Cuprates, https://en.m.wikipedia.org/wiki/Cuprate , to quote:
"One of the simplest oxide-based cuprates is the copper(III) oxide KCuO2, a dark blue diamagnetic solid. It is produced by heating potassium peroxide
and copper(II) oxide in an atmosphere of oxygen:
K2O2 + 2 CuO → 2 KCuO2"
Also, same article, quoting:
"The light blue solid sodium tetrahydroxycuprate is well known, it is prepared by heating cupric hydroxide with concentrated sodium hydroxide.[12]
Cu(OH)2 + 2 NaOH → Na2Cu(OH)4 "
which suggests to me, we may have just prepare a double salt, namely: Cu(OH)2.2NaOH, and the oxide above similarly: K2O2.2CuO. If this is an accurate
assessment, general properties of mixed salts may apply, like preparation technique (stirring hot concentrated mixtures of the individual salts
especially when freshly precipiated, or nano-sized...), a distinct new crystal structure, and upon dissolving, reversion to the original individual
salts and their respective properties. The last point, implies possibly, for example, per the reaction cited below with water:
2 KCuO2 + H2O --?→ 2 CuO + 2 KOH + 1/2 O2
----------------------------------------------
The K2O2 can be formed when potassium metal reacts with oxygen in the air (along with potassium oxide (K2O) and potassium superoxide (KO2) ). Note, no
moisture as:
K2O2 + H2O → 2 KOH + 1/2 O2
Source: Wikipedia again: https://en.m.wikipedia.org/wiki/K2O2
[Edited on 16-11-2015 by AJKOER]
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AJKOER
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Found a good reference on a related topic ferrate salts, "Ferrate(VI) in the Treatment of Wastewaters: A New Generation Green Chemical ", by
Diwakar Tiwari and Seung-Mok Lee, link: http://www.intechopen.com/books/waste-water-treatment-and-re... .
Many preparation paths appear similar, for example, to quote from page 243:
"Sodium ferrate(VI) was obtained by taking Fe2O3-NaOH-Na2O2-O2 at different temperatures. Moreover, the fusion of Na2O2 with Fe2O3 at a
molar ratio under dry oxygen conditions at high temperature, yields sodium ferrate(VI).'
Also, interestingly, a parallel to my speculated reaction of KCuO2 and water producing oxygen. To quote from page 253:
"The ferrate salts when dissolved in water, oxygen is evolved and ferric hydroxide is precipitated (equation (14)).
4K2FeO4 + 10H2O → 4Fe(OH)3 + 8KOH + 3O2 "
[Edited on 17-11-2015 by AJKOER]
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