Sodium sulfide is the chemical compound with the formula Na2S, or more commonly its hydrate Na2S·9H2O. Both are colorless water-soluble salts that give strongly alkaline solutions. When exposed to moist air, Na2S and its hydrates emit hydrogen sulfide, which smells like rotten eggs. Some commercial samples are specified as Na2S·xH2O, where a weight percentage of Na2S is specified. Commonly available grades have around 60% Na2S by weight, which means that x is around 3. Such technical grades of sodium sulfide have a yellow appearance owing to the presence of polysulfides. These grades of sodium sulfide are marketed as 'sodium sulfide flakes'. Although the solid is yellow, solutions of it are colorless.
Sodium sulfide is a chemical compound with the formula Na2S and its hydrated form with the formula Na2S.9H2O, both of which are water-soluble salts and produce strong and colorless alkaline solutions. Although sodium sulfide is a yellow solid, its solution is colorless. Sodium sulfide is produced in crystallized, cracked and broken forms and releases hydrogen sulfide gas when exposed to air, which smells like rotten eggs. Sodium sulfur reacts with hydrogen peroxide to produce sodium sulfate.
