A byproduct of burning phosphorous compounds, P4O10 is a white to yellow crystalline solid (granular) and a powerful desiccant and potent dehydrating agent powerful enough to dehydrate sulfuric acid into sulfur trioxide as well as amides to nitriles. The solid reacts violently with water forming phosphoric acid which is used in applications such as; electrolytes, metal cleaning, rust removal, soldering flux, etchants, cleaning solutions, Ph adjuster, fertilizers and pesticides, phosphoric acid production, fertilizers, metal etchants, soldering flux & pesticides.Caution; Keep containers well sealed in a dry area and store seperate from organic and/or combustible materials. Contaminated with combustible material, it can heat and cause fire with the induction of moisture. Corrosive!