Ammonium metatungstate (AMT) is a white or yellowish crystalline powder, an important tungsten compound which can be used for producing tungsten oxide, tungsten powder and other products, or for the manufacture of all kinds of catalyst in petroleum chemical industry, the main raw material of tungsten based catalyst of oil refineries.

 

If there are no special instructions, the solubility of ammonium metatungstate refers to it in water; AMT has very good water soluble which is 303.99/100g at 20℃, and its aqueous solution is quite stable with acidity. With the improving of temperature, ammonium metatungstate solubility in water will raise until it reaches the highest solubility which is saturated state. Metatungstic acid and most of its metatungstate can well soluble in water, and the advantage of AMT is its very huge solubility in water, thus it can be directly used and to prepare high concentrated tungstate solution with no alkali metal ions.

 

Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent. The solubility of a substance fundamentally depends on the physical and chemical properties of the solute and solvent as well as on temperature, pressure and the pH of the solution. The extent of the solubility of a substance in a specific solvent is measured as the saturation concentration, where adding more solute does not increase the concentration of the solution and begins to precipitate the excess amount of solute. The solubility of a substance is an entirely different property from the rate of solution, which is how fast it dissolves.

 

The factors that affect solubility are temperature, pressure ect.. Solubility is defined for specific phases. For example, the solubility of aragonite and calcite in water are expected to differ, even though they are both polymorphs of calcium carbonate and have the same chemical formula. The solubility of one substance in another is determined by the balance of intermolecular forces between the solvent and solute, and the entropy change that accompanies the solvation. Factors such as temperature and pressure will alter this balance, thus changing the solubility.