Sciencemadness Discussion Board

Copper (II) Permangante solubility info?

bolbol - 7-3-2015 at 16:19

I am having a hard time finding information on how soluble copper permanganate is in water.I have some Silver Nitrate thats contaminated with a fair amount of copper nitrate and I wanted to make Silver permanganate and filter of the remainder... IF copper permanganate is in fact soluble

gdflp - 7-3-2015 at 16:25

This claims it's soluble, not sure if I would trust it though. I tried three editions of the CRC, it wasn't listed in any of them. Why not try with dilute potassium permanganate and dilute copper sulfate and see if a precipitate is formed?

bolbol - 7-3-2015 at 16:28

Yeah I found that too but "soluble" could very well mean 0.1 gram in 100 ml of water lol

I'll just prepare some copper nitrate and try it out then i guess

chem_haruka - 8-3-2015 at 04:34

If you want to separation silver nitrate and copper nitrate,heat it!
The silver nitrate won't decompose under 400°C .However, copper nitrate will decompose under 170℃.
The decompose products of copper nitrate(3 H2O) are water,NOx(gas),and CuO(insoluble in water).Dissolved in water， filter out CuO ，then evaporative crystallization.

gdflp - 8-3-2015 at 08:43

Just tried an experiment to see if copper permanganate was soluble. ~1ml of 1M cupric sulfate was placed in a test tube and a dilute solution of potassium permanganate, ~0.02M diluted from a 0.1M stock solution, was added dropwise. The solution first turned a navy blue color similar to that of the copper tetramine complex, but slowly the color changed to a purple color. This purple is very different from that of potassium permanganate though, it's much more of a violet purple than the pinkish purple of KMnO4 if that makes any sense. If anyone wants, I can post a picture of the solution. No precipitation was observed.

Amos - 8-3-2015 at 15:04

Quote: Originally posted by gdflp  
Just tried an experiment to see if copper permanganate was soluble. ~1ml of 1M cupric sulfate was placed in a test tube and a dilute solution of potassium permanganate, ~0.02M diluted from a 0.1M stock solution, was added dropwise. The solution first turned a navy blue color similar to that of the copper tetramine complex, but slowly the color changed to a purple color. This purple is very different from that of potassium permanganate though, it's much more of a violet purple than the pinkish purple of KMnO4 if that makes any sense. If anyone wants, I can post a picture of the solution. No precipitation was observed.


That sounds kind of like a mixture of pinkish-purple permanganate and blue copper sulfate, both in solution.

woelen - 9-3-2015 at 00:08

Nearly all permanganates are very soluble (at least tens or even hundreds of grams per 100 ml of water) and extremely hygroscopic. There are just a few sparingly soluble ones:

KMnO4
RbMnO4
CsMnO4
AgMnO4
TlMnO4 (unstable, will internally rearrange to a basic Tl(III) salt of a lower manganate).

All others can be considered very soluble.

Maybe there also are some sparingly organic permanganate salts (e.g. N(CH3)4MnO4), but I never tried. I have experience with perchlorate salts of a few of these, probably the permanganate salts have similar solubility properties. Unfortunately I only have KMnO4, which itself is only sparingly soluble, so trying to make other permanganate salts is not really easy. I have tried to find a source of NaMnO4 but I have never seen that sold online.

[Edited on 9-3-15 by woelen]

Sulaiman - 9-3-2015 at 03:35

The subject of silver refining has come up many times, recap;

.if there is just a little copper nitrate, refine silver nitrate by recrystalisation

.if there is a lot of copper nitrate, neutralise any nitric acid,
use copper metal/wire to precipitate silver metal particles by substitution, filter and wash.
Now choose;
.melt silver into a solid and refine by electrolysis
.'disolve' silver precipitate in nitric acid, evaporate off the liquid, recrystalise the silver nitrate.

wear gloves!

I must admit, my efforts so far have not produced silver nitrate so pure that it is not sunlightlight sensitive.
I haven't given up, I'm going to do a second recrystalisation sometime.

[Edited on 9-3-2015 by Sulaiman]

blogfast25 - 9-3-2015 at 07:16

Copper(II) permanganate is water soluble. Obviously in solution its colour will be different from permanganates with colourless cations.

Bezaleel - 12-3-2015 at 04:38

Quote: Originally posted by Sulaiman  
(...)
I must admit, my efforts so far have not produced silver nitrate so pure that it is not sunlightlight sensitive.
I haven't given up, I'm going to do a second recrystalisation sometime.

[Edited on 9-3-2015 by Sulaiman]


Somewhat off-topic: what type of impurity is it that makes silver nitrate sunlight sensitive? Other d-block cations? Or silver/silver oxide nanoparticles?

bolbol - 30-3-2015 at 13:29

Kind of off-topic since I didn't bother at all with copper permanganate but I was able to make some Silver Permanganate which I initially thought would be hard to pull off since wikipedia had it stated that it decomposes in water. I did some more research and found an article about it which stated that an excess solution of AgNO3 with KMnO4 would yield Silver Permanganate precipitates. I tried it with 13 grams of AgNO3, mixed up everything in around 350mls of distilled water. Filtered everything and washed the filter paper under running water and ended up with 13 grams of what I believe is AgMnO4. The yield was very bad, around 50%, and that is mostly due to the washing of the precipitate with water to get rid of residual AgNO3 since AgMnO4 is somewhat soluble in water.

I noticed that when dropped on the ceramic sink it left a brown residue while pure KMnO4 did not. But I still wasn't sure of the purity so I did the KMnO4 + Glycerin + water experiment. With this product when the reaction got going there was no colored flame which is a characteristics of Potassium
Here is a picture:
http://i59.tinypic.com/2rh5lds.jpg


[Edited on 30-3-2015 by bolbol]