Silver Nitrate Concentrate

[martellsv]

I have a problem with my Silver Nitrate 12% concentrate un 100 cc of distilled water.

Completely disolved but on the second day appears a precipitate. I don't know why...
Thanks

 

[koraks]

Contamination with some salt most likely. What kind of water did you use? And was the concentrate clear when you just made it or was it milky?

 

[Photo Engineer]

Silver metal forming, or perhaps some Silver Oxide?

PE

 

[koraks]

Sorry, you wrote distilled water.

Was the container clean?

 

[martellsv]

Probably the container i use todo mesure not clean...
Thanks

 

[nmp]

Probably the container i use todo mesure not clean...
Thanks

Might have also got exposed. It would be a good idea to store it in an amber-colored bottle.

 

[NedL]

That looks like a lot of precipitate, is it possible you dipped a brush into it or there was some other source of contamination?

I've noticed a fine black precipitate ( similar color as yours, but not nearly so much ) forms over a long time in silver nitrate solution. It's always perfectly clear when I first make it but over a period of months and years the precipitate sticks to the bottle and glass eyedropper in it. Just a few weeks ago I switched to a new clean eyedropper bottle after using the old one for about 5 years ( it's been refilled many times ) because of this. My ( maybe wrong! ) idea is a very slow reaction with dissolved gasses, like maybe carbonic acid. The silver oxide I've seen is more brown, but maybe there is variation in its color. I do have a sense that it happens more when the bottle is mostly empty. Anyway, it's never caused me any problems and I don't know that it was really necessary for me to use a new eyedropper bottle.

My fixer bottles are more fun.. the silver precipitates out as a mirroring on the glass that is very pretty!

 

[koraks]

Might have also got exposed. It would be a good idea to store it in an amber-colored bottle.

My silver nitrate solutions are in clear bottles. Other than some minor silver plating, it doesn't cause any issues. Silver nitrate in solution isn't light sensitive.

 

[nmp]

My silver nitrate solutions are in clear bottles. Other than some minor silver plating, it doesn't cause any issues. Silver nitrate in solution isn't light sensitive.

Unless you have impurities.

 

[NedL]

I don't know much about it, but I know some people who reuse silver nitrate solutions in processes that introduce contaminants ( like making calotypes, or float-sensitizing salt or albumen prints ) "sun" their silver nitrate solution to encourage the contaminants to precipitate out. Then the solution is filtered or mixed with kaolin so that the precipitates will settle to the bottom and decanted.

I tried it one time with a beaker of silver nitrate that had been used to make calotypes... left it in a sunny window for 1/2 hour, but I didn't notice anything precipitate out, and it was still perfectly clear when I filtered it back into its bottle. I've always wanted to know more about this. My calotypes usually don't have a lot of extra whey or lactose or starch or other things that would contaminate the silver solution, so it probably wasn't necessary when I tried it.

 

[mshchem]

I used to make 1 molar silver nitrate solutions (nearly 17%) used ultra pure DI water never had a bit of problem. Get city water anywhere near it you get AgCl ppt. Any ordinary copper, tin etc will plate out silver. Find a nice little flask with a ground glass or better plastic stopper.

 

[koraks]

Unless you have impurities.

Like NedL says, they expose and turn into metallic silver, and settle to the bottle when exposed to light. I use demineralized water for my silver solutions, and it always has some trace chlorine in it. This results in a tiny fraction of silver chloride that is disposed of in the way described.