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Oxidizer for silver nitrate

Thanks for taking the time to answer my question , I need to find a moderately benign solution to oxidize the silver nitrate coating on a mirror ....I do glass work and need a answer that does not include nitric acid...thanks ,

Scott Barlow
artistic glass - Albuquerque, New Mexico
2007

Coating on mirror is silver not silver nitrate (silver nitrate can be used in mirror silvering process)-try potassium or sodium sulfide solution (0,5-2%). Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
2007

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I think there is a bit of confusion here. Firstly, the coating on a mirror is silver, not silver nitrate, but it is usually deposited by reducing a silver nitrate solution. consequently, you cannot oxidise the silver nitrate as it is already oxidised, but you can reduce silver nitrate to silver. Conversely, you can reduce silver nitrate to silver metal with a reducing agent. I think you are trying to remove the silver from an old mirror or something and then re-coat it with fresh silver. If I am correct, you need to oxidise the silver coating, and the best solution for this is nitric acid. I appreciate you don't want to use it, but even cold dilute nitric acid will dissolve silver, but will not attack the glass. However, if you are trying to protect something else form attack by nitric acid, that throws a different complexion on the problem and without knowing what you are trying to protect, I cannot give an answer. Alternatively, you could use an excess of potassium cyanide solution, but this is extremely hazardous and should not be undertaken by anyone who is not accustomed to handling highly toxic chemicals. Potassium cyanide may also attack other metals, so be careful. A final suggestion is to use mercury and make an amalgam. Just continually rub mercury over the silver and it will "dissolve" into the mercury to create a powder. However, mercury is very poisonous and should be treated with respect and use a lot of safety precautions, such as rubber rubber gloves ⇦ this on eBay or Amazon [affil links] and avoid inhaling any vapours, so it is probably best to do this in a cold environment and in a fume cupboard.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2007