Diphosphorus pentoxide, with the chemical formula P4O10, is a highly reactive compound formed when phosphorus reacts with oxygen. This white powder is an acid anhydride, meaning it reacts with water to form an acid (phosphoric acid). As a desiccant, it absorbs moisture from its surroundings, making it useful for drying gases and liquids. Diphosphorus pentoxide is also employed as a catalyst in organic synthesis and as a food additive to prevent spoilage.