Ammonium tetramolybdate physical properties

Ammonium tetramolybdate is a chemical compound with the molecular formula (NH₄)₂Mo₄O₁₃. It is a molybdenum compound that is commonly encountered in chemical laboratories and industrial processes. Here are some key aspects of ammonium tetramolybdate:

1. Chemical Structure:

The compound consists of ammonium ions (NH₄⁺) and a polymeric anion composed of four molybdenum atoms (Mo₄) surrounded by oxygen atoms. The molecular formula reflects the presence of four ammonium ions for each tetramolybdate unit.

2. Appearance:

Ammonium tetramolybdate is often encountered as a white or slightly yellow crystalline powder. Its physical form may vary depending on factors such as hydration.

3. Synthesis:

It can be synthesized by reacting molybdenum trioxide (MoO₃) with ammonium hydroxide (NH₄OH). The resulting product can undergo further processing to obtain different forms, including hydrates.

4. Applications:

Ammonium tetramolybdate has several applications, most notably in the preparation of catalysts, particularly for the synthesis of heteropoly acids and other molybdenum-containing compounds.

It is also used in the production of molybdenum metal, which finds applications in the metallurgical and aerospace industries.

In analytical chemistry, ammonium tetramolybdate is employed as a reagent for the determination of phosphates.

5. Catalysis:

As a source of molybdenum, ammonium tetramolybdate is a precursor in the synthesis of various catalysts used in chemical processes, such as oxidation reactions and desulfurization of fuels.

6. Solubility:

Ammonium tetramolybdate is typically soluble in water. The solubility may vary with temperature and the specific hydrate form.