Ammonium Metatungstate and Ammonium Paratungstate Difference

Difference between ammonium metatungstate (AMT) and ammonium paratungstate (APT) firstly reflects in their molecular structure, as shown below:

ammonium metatungstate formulaammonium paratungstate formula

Difference of formula:
1. Ammonium metatungstate formula: (NH4)6H2W12O40.nH2O or (NH4)6H2W12O40.XH2O or (NH4)6H2W12O40
2. Ammonium paratungstate formula has several forms depending on the different crystallization conditions, as follows: 3(NH4)2O-7WO3-6H2O ;(2)5(NH4)2-12WO3-5H2O; (3)5(NH4)2O-12WO3-5H2O ;(4) 5(NH4)2O-12WO3-11H2O

Solubility differences:
1. Ammonium metatungstate has good water solubility of 303.99/100g at 20℃ with quite stable, but insoluble in alcohol;
2. Ammonium paratungstate is slightly soluble in water with water solubility less than 2% at 20℃, also insoluble in alcohol.

Difference on production:
The biggest difference of production between ammonium metatungstate and ammonium paratungstate is that APT is raw material of AMT, and thermal degradation of APT to generate AMT is a typical process of the solid phase transformation.

Difference on application:
Ammonium metatungstate used for preparing tungsten metal powder, alloy steel and tungsten compounds, while also used in the nuclear shielding materials and corrosion inhibitor;
Ammonium paratungstate is mainly for the manufacture of or tungsten trioxide or blue tungsten oxide, thus to prepare metal tungsten powder; and used as a laboratory reagent for preparing high purity tungstic acid, tungsten metal powder or tungsten carbide, and water-absorbing gel ect..

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1.Tungsten Trioxide

2.Tungsten Oxide