vano
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Silver in hydrogen peroxide
Hi, i made silver mirror reaction, then washed beaker and added concentrated H2O2, then silver dissolved. Solution was transparent. I did some tests,
when i added sodium chloride silver chloride was formed. Next i boiled solution and when it dry it was white and it explode with noise sound. I think
it is a peroxocompound of Silver. Does anyone know formula or reactions?
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VeritasC&E
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Could it be Silver(I,III) oxide + H2O2?
Silver is a known catalyst and peroxides are all quite sensitive.
It could also be copper in the silver if it's impure (forming CuO2 in its own right).
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VeritasC&E
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I think pretty much any metal impurities increases the instability of H2O2, Cu & Ag probably being amongst the most performant at it.
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vano
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Solution was clear. Also i dont know why it exploded. I know silver is catalyst in high concentrated peroxide decomposition process, but i think this
situation is different.
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woelen
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Silver(I, III) oxide, Ag2O2, is dark grey, almost black. I have made that compound a few times. It cannot be made from H2O2, but it can be made from
Na2S2O8, AgNO3, and very dilute HNO3.
I once observed the white solid, you mention, but it did not explode. I cleaned a tarnished piece of silver. I used dilute H2O2 at high pH for that
and observed formation of a white layer on the metal, which was not easily removed from the metal. I did not heat the metal, I just let it dry on
contact with air.
This sounds like an interesting find. Interesting to do some investigations on this. Maybe I find some time this weekend for that.
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vano
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What do you think what is this white compound ?
It explosion sound was like hydrogen explosion, very very fast. Also next i saw brown layes, i think it was oxide.
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Triflic Acid
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Silver oxide is grey, not brown. Might be copper contamination. What was your silver source? If it was bought from a jeweler, it might have been used
to inquart gold, leaving the copper in the silver.
There wasn't a fire, we just had an uncontrolled rapid oxidation event at the power plant.
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vano
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Quote: Originally posted by Triflic Acid  | | Silver oxide is grey, not brown. Might be copper contamination. What was your silver source? If it was bought from a jeweler, it might have been used
to inquart gold, leaving the copper in the silver. |
Yes you are right. It really had brown colour, but it was very thin layer. I did it at laboratory, silver nitrate was here, it was labgrade nitrate,
not from sterling silver or such things.
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Bezaleel
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In my experiments with silver, I've seen that when silver chloride oxidises, it turns from white to yellow to brown and then to a very dark colour. So
maybe your brown layer is a mixed oxide-chloride compound?
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vano
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I didn't have chloride anion in solution. But i think brown colour for oxide os possible and its depends on particles size.
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Bezaleel
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Oh, sorry, I read your first post as having silver, H2O2 and NaCl in solution.
A brown colour may also show up with a "black" compound if the layer is really thin. When silver tarnishes, it usually becomes brown first, and black
when it tarnished further.
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vano
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| Quote: Originally posted by Bezaleel |
A brown colour may also show up with a "black" compound if the layer is really thin. When silver tarnishes, it usually becomes brown first, and black
when it tarnished further. |
Yes i agree with you.
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