What Is Ammonium Paratungstate

Ammonium Paratungstate Picture

What is ammonium paratungstate? Ammonium paratungstate (APT) is a kind of white crystal with two forms of flake and needle, slightly soluble in water, insoluble in alcohol; it is mainly used for manufacturing ammonium metatungstate (AMT), tungsten trioxide (WO3) and blue tungsten oxide ect., and also being the raw material of other tungsten compound; others, APT can also be used to produce catalyst.

Chinese Name: 仲钨酸铵
English Name: Ammonium Paratungstate
English Abbreviation: APT
Molecular Formula: H8N2O4W
Molecular weight: 283.9145
Melting Point: 3410 °C(lit.)
Boiling Point: 5660 °C (lit.)
Density: 4.61g/cm3
EINECS: 234-364-9
CAS Number: 11120-25-5
Dangerous Goods Mark: F,Xi
Hazard Category Code: 11-36/38-36/37/38
Safety Instructions: 6-26-36
Dangerous Goods Transport No.: UN 3089 4.1/PG 2
RTECS Number: YO7175000
Hazard Class: 8
APT will have forms of crystal under different crystallization conditions, such as:
1.3(NH4)2O-7WO3-6H2O ;
2.5(NH4)2-12WO3-5H2O;
3.5(NH4)2O-12WO3-5H2O;
4.5(NH4)2O-12WO3-11H2O
Appearance: White crystal with two forms of flake and needle.
Solubility: Slightly soluble in water (the solubility is less than 2% in water under 20℃) and will increase slightly with the raising of temperature, insoluble in alcohol.
Thermal Decomposition: Ammonium paratungstate will lose part of ammonia and water when heated to 220~280℃ and transferred into ammonium metatungstate (AMT); when heated to 600℃ or higher temperature, APT will lose all the ammonia and water and become yellow tungsten trioxide completely.

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