What Is The Crystal Water of Ammonium Paratungstate? 2023-02-24 Tungsten Oxide 237 The chemical formula of ammonium paratungstate is (NH4) 2W2O7, and the amount of crystal water depends on its crystallization conditions. In the standard state, the chemical formula of its anhydrous substance is W2O5, without crystal water. 0 0 ammonium paratungstatecrystal water