The usually known of ammonium paratungstate hydrate is tetrahydrate and decahydrate APT, the formation of different hydrates is depended on the extraction temperature, and the molecular formulas are:
[(NH₄)₁₀ H₂W₁₂O₄₂]?4H₂O
[(NH₄)₁₀ H₂W₁₂O₄₂]?10H₂O
EINECS NO.: 234-364-9
Melting Point: 3410 °C(lit.)
Boiling Point: 5660 °C (lit.)

Ammonium paratungstate hydrate can be shorted of APT, the important intermediate for producing tungsten oxide, metal tungsten, tungsten based catalyst and carbide (such as tungsten carbide), also the APT reagent can be used in composition analysis, research and other fields. The storage conditions of APT reagent maybe in the -20°C, avoid light, airtight, moistureproof, dry place. According to the actual chemical purity level, the ammonium paratungstate hydrate is suitable for the important analysis of and general research, often expressed in AR.