What causes silver articles to turn black when exposed to air, and what is the coating formed on silver as a result of this reaction?

Silver articles turn black when exposed to air due to a chemical reaction with sulfur compounds in the environment, forming silver sulfide (Ag2S). This reaction is known as tarnishing. Sulfur compounds, such as hydrogen sulfide present in air or substances like rubber and certain foods, react with the silver surface, creating a dark layer of silver sulfide on the metal. The silver sulfide coating is black and adheres to the surface, causing the silver to lose its original luster. Polishing or using silver cleaners can remove this tarnish and restore the shine by removing the outer layer of silver sulfide.