Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Why Does Silver Tarnish?
Q. Hello, I am in organic chemistry class and today we received a handout asking why and how silver tarnishes. I know it has to do with silver oxidizing, however, I'm not completely sure as to why or how. Does the presence of sulfur, cause the tarnish on the silver?
If anyone could help me I would greatly appreciate it.
C. Benson- Houston, Texas USA
2001
A. Silver sulphate is the principle product formed when silver turns dark colored (tarnishes). There is sulfur ⇦ this on eBay or Amazon [affil links] containing compounds in air, and most papers, so to prevent tarnish, one needs to prevent contact of the silvered item with air by storing it in an air tight, sulfur-free container, or, if viewing is desired, applying a tightly adhering clear film such as a lacquer.
W. Carl Erickson- Rome, New York
2001
A. Tarnish is what happens to silver when silver becomes silver sulfide. You can see this by looking at silver and looking for a dark black color. This happens when the sulfide in the spoon or metal reacts with the air around it
Amanda D.- Menomonee Falls, Wisconsin, USA
2003
Q. Why does silver tarnish ?
Marilyn K Priceteacher - Phila, Pennsylvania, USA
2004
A. Hi. For all metals except precious metals like gold and platinum, the oxidized or sulfided state is a lower energy state than the raw metal state. So sulfur in the air will react with silver and leave a black tarnish on it, very slowly releasing a small amount of heat when it does so.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003
!! My silver ring recently turned black, and seeing how I have been wearing it for years without such a reaction I got to wondering what could have caused this. Then I read your reader response on sulfur and realized it must be the sulfur soap I have started using on my face. Lesson learned: Take off your silver jewelry when washing your face with sulfur products!
Panja Cantala- EL Paso, Texas
2007
A. Tarnished silver can be cleaned with boiling water and baking soda [in bulk on eBay or Amazon [affil links]
Rena Kouper- Christchurch, New Zealand
February 16, 2009
Thanks Rena. I think that's a slight simplification though. The silver must be touching an aluminum cleaning plate, or at least aluminum foil, for that to work. It's explained in letter 4785, "Polishing Silver with Aluminum Foil and Baking Soda".
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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