Phosphotungstic acid (PTA), tungstophosphoric acid (TPA), is a heteropoly acid with the chemical formula H3PW12O40nH2O. It is normally isolated as the n = 24 hydrate but can be desiccated to the hexahydrate. EPTA is the name of ethanolic phosphotungstic acid, its alcohol solution used in biology.

Application

hosphotungstic acid (PTA), tungstophosphoric acid (TPA), is a heteropoly acid with the chemical formula H3PW12O40nH2O. ... It has the appearance of small, colorless-grayish or slightly yellow-green crystals, with melting point 89 °C (24 H2O hydrate). It is odorless and soluble in water