phosphorus pentoxide

noun

: a compound known in various polymeric forms (P₂O₅)_x (as the dimer P₄O₁₀ in the vapor and one crystalline modification) that is obtained usually by burning phosphorus in an excess of dry air and occurs as a white powder that reacts vigorously and sometimes explosively with water to form phosphoric acids irritating to the skin and mucous membranes, and is used chiefly as a drying agent, as a condensing agent in organic synthesis, and in making phosphoric acids and derivatives; di-phosphorus pentoxide — called also phosphoric anhydride

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/pen tok"suyd, -sid/, Chem.

a white, deliquescent, crystalline powder, P₂O₅, that, depending upon the amount of water it absorbs, forms orthophosphoric acid, metaphosphoric acid, or pyrophosphoric acid, produced by the burning of phosphorus in dry air: used in the preparation of phosphoric acids, as a drying and dehydrating agent, and in organic synthesis. Also called phosphoric anhydride.