Sodium sulfide is a chemical compound with the formula Na2S. It consists of sodium ions and sulfide ions, and it appears as a yellow to red solid. Sodium sulfide is highly soluble in water, forming a strongly alkaline solution. It is commonly used in various industrial processes, including paper manufacturing and water treatment. In addition to its industrial applications, sodium sulfide is also used in the production of sodium thiosulfate, a compound important in photography and water purification. However, sodium sulfide can be hazardous, as it releases toxic hydrogen sulfide gas when it reacts with acids. Proper safety measures are essential when handling this compound.