Sulfide (systematically named sulfanediide, and sulfide(2−)) is an inorganic anion of sulfur with the chemical formula S 2− .It contributes no color to sulfide salts. As it is classified as a strong base, even dilute solutions of salts such as sodium sulfide (Na 2 S) are corrosive and can attack the skin.issolved free sulfides (H 2 S, HS − and S 2−) are very aggressive species for the corrosion of many metals such as steel, stainless steel, and copper. Sulfides present in aqueous solution are responsible for stress corrosion cracking (SCC) of steel, and is also known as sulfide stress cracking.