Sciencemadness Discussion Board - Unique silver compounds

Unique silver compounds

symboom - 9-2-2017 at 15:19

Silver nitrate is combined with these salts

Sodium oxalate
Sodium citrate
Sodium ascorbate
Sodium metabisulfite
Sodium acetate
Sodium chlorocyanurate
Sodium borate....
Sodium silicate...
Magnesium sulfate
Sodium hypochlorite

Insouble yellow silver oxalate

Silver citrate formed is soluble

Sodium ascorbate forms black solid?

Sodium metabisulfite forms pink solid?

Insoluble white silver acetate

Sodium chlorocyanurate forms white percipitate?

silver sulfate slight white cloudyness

silver hypochlorite forms white percipitate
And a little black precipitate

Side notes
Reactions with copper foil
Also if anyone needs copper foil
I extracted mine from a lithium ion battery

Silver acetate
Big chunks spall off the copper foil
Silver citrate
Strongly adheres to the copper foil
Silver sulfate
Percipitate forms on copper surface

[Edited on 9-2-2017 by symboom]

[Edited on 10-2-2017 by symboom]

[Edited on 10-2-2017 by symboom]

DraconicAcid - 9-2-2017 at 15:22

The black solid formed by the reaction with ascorbate is probably metallic silver. Ascorbic acid is a reducing agent.

myristicinaldehyde - 9-2-2017 at 16:02

I would guess the pink precipitate is silver sulfite, which apparently decomposes very readily on exposure to light- this would be the pink color. I am basing the color source off my experience with silver chloride.

A proof of decomposition causing the pink color rather than the salt itself would be to make some fresh in dim light, then put it in the sun or a UV light. If it is sulfite, then if you wash it very thoroughly (out of the light) and add a little bit to acid, SO2 should be given off.

Eddygp - 10-2-2017 at 08:22

Quote: Originally posted by DraconicAcid

The black solid formed by the reaction with ascorbate is probably metallic silver. Ascorbic acid is a reducing agent.

Why not silver(I) oxide?

woelen - 10-2-2017 at 11:29

Not silver(I) oxide. Silver(I) oxide, when formed in water, is not black, but dirty brown. This is hydrous silver(I) oxide. And indeed, ascorbate is a sufficiently strong reductor to reduce silver(I) to metallic silver. It also is capable of reducing copper(II) to copper(I).

With bleach you get silver(I) chloride, but you can get a black compound, silver(I) silver(III) oxide, AgAgO2. Hypochlorite is a very strong alkaline oxidizer and it is capable to oxidize silver to its +3 oxidation state. In this oxidation state it hydrolyses at once and forms a mixed oxidation state oxide.

PHILOU Zrealone - 10-2-2017 at 13:01

Quote: Originally posted by woelen

Not silver(I) oxide. Silver(I) oxide, when formed in water, is not black, but dirty brown. This is hydrous silver(I) oxide. And indeed, ascorbate is a sufficiently strong reductor to reduce silver(I) to metallic silver. It also is capable of reducing copper(II) to copper(I).

With bleach you get silver(I) chloride, but you can get a black compound, silver(I) silver(III) oxide, AgAgO2. Hypochlorite is a very strong alkaline oxidizer and it is capable to oxidize silver to its +3 oxidation state. In this oxidation state it hydrolyses at once and forms a mixed oxidation state oxide.

Silver (III) can be stabilized in water if complexed with ethylenebis(biguanide) and forms then a [ethylenebis(biguanide)silver(III) cation that can fix nitrate or perchlorate anion
--> [Ag(H2L)]³⁺ + 3 NO3^(-) or 3 ClO4^(-)...
Probably energetic

symboom - 10-2-2017 at 14:21

Quote: Originally posted by woelen

With bleach you get silver(I) chloride, but you can get a black compound, silver(I) silver(III) oxide, AgAgO2. Hypochlorite is a very strong alkaline oxidizer and it is capable to oxidize silver to its +3 oxidation state. In this oxidation state it hydrolyses at once and forms a mixed oxidation state oxide.

Thank you for the response
I read that silver hypochlorite is formed and disproportionates to silver chloride and silver chlorate

Edit(woelen): Fixed layout issue.

[Edited on 13-2-17 by woelen]

woelen - 13-2-2017 at 00:06

I don't think that silver hypochlorite can form from bleach. Bleach is quite alkaline and under such conditions, you will get silver oxide. Even with pure hypochlorite, not containing chloride, I expect formation of the black mixed +1/+3 oxide.

phlogiston - 13-2-2017 at 06:16

Can the slight turbidity observed with sulfate be explained by a slight contamination with lead?
What is the source of your silver nitrate?

When bleach is used to reclaim silver from the gelatine layer of x-ray film, one obtains a white precipitate of (what seems to me to be) silver chloride. When exposed to sunlight, it converts into a black powder. If kept in the dark, even though bleach is very alkaline it remains white for at least a few days. Addding concentrated NaOH converts the precipitate to a black powder 'instantly'.