Diethyl sulfide is a clear flammable chemical compound with a pungent garlic-like odor. It has the chemical formula C
10S, though it can also be written (C
2S or Et
2S to make its chemical structure more clear. It is prepared by treating ethanol with concentrated sulfuric acid, partially neutralizing the new solution with sodium carbonate, then distilling the resulting sodium ethyl sulfate in a solution containing potassium sulfide.