Grey Silver Nitrate Crystals

[tgtaylor]

B&S used to ship silver nitrate in small brown bottles. Then at some point they switched to big (for 30 grams) white plastic bottles. One of those plastic bottles got pushed behind the other chemistry in my covert and I lost track of it and I re-ordered without knowing that I had it. When I rediscovered it the crystals had turned a grey color. I don't know how long ago that I had ordered it but it can't be too long. It was kept with the cap tightly closed in a dark place and never openly exposed to the environment. Could the white plastic container be the cause of the color change? Having used the last of working solution this morning, I mixed up another 100mL of working solution. I found a small brown bottle with ~3.5 gms in it and used it along with SN in another white brown bottle plastic bottle. Both had good color but I can't remember if the brown bottle was from last order or not.

Thomas

[LabRat]

I have heard that silver nitrate gets "old"... You can test it... "Grey" is probably oxidation...

Steve K

[Cor]

Thomas,

I have been using very old ( >40 years old) greyish SilverNitrate without a problem. You could make a solution (in distilled water, but you knew that) with it, perhaps put it in the sun (just like in wet plate work, the UV in the sun will make possible reactions between the contamination (if present) and the silver nitrate, and than filter the solution.

Good luck,

Cor

[tgtaylor]

Thanks for the replies everyone!

I did some checking and found a post on apug by Dana Sullivan on this very question. He suggests putting the grey crystals into solution and if the resultant is clear then the silver is good. I'm going to test this and report back on the results of that test.

Thomas