Ammonium metatungstate (AMT) can be synthesized by reacting sodium tungstate with ammonium chloride in aqueous solution, followed by acidification with hydrochloric acid. The reaction can be summarized by the following equation:
Na2WO4 + 2NH4Cl + H2SO4 → (NH4)6H2W12O40·xH2O + 2NaCl + 2H2O
In this reaction, sodium tungstate (Na2WO4) and ammonium chloride (NH4Cl) are dissolved in water and then mixed together. Sulfuric acid (H2SO4) is added to acidify the solution, which results in the formation of ammonium metatungstate as a precipitate. The precipitate is then filtered, washed, and dried to obtain the final product.
The reaction conditions such as temperature, pH, and reactant concentrations can affect the yield and quality of the final product. The synthesis process can also be modified by using different tungsten sources or different ammonium salts.
