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topic 7447

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


A. Silver sulfate is the principle product formed when silver turns dark colored (tarnishes). There is sulfur 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


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

(2004) -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Why does silver tarnish ?

Marilyn K Price
teacher - Phila, Pennsylvania, USA

3M Silver Protector Strips


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, Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey


!! 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

February 16, 2009

A. Tarnished silver can be cleaned with boiling water andbaking soda [linked by editor to product info at Amazon]

Rena Kouper
- Christchurch, New Zealand

Electrolytic Cleaning Plate

thumbs up signThanks 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".


Ted Mooney,
Teds signature
Ted Mooney, P.E.
Pine Beach, New Jersey

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