Ammonium dimolybdate, also known as ammonium molybdate, is a chemical compound with the formula (NH4)2Mo2O7. It is composed of ammonium cations (NH4+) and dimolybdate anions (Mo2O7^2-). Ammonium dimolybdate has several uses in various fields:

1. Catalyst: Ammonium dimolybdate is used as a catalyst in various chemical reactions, particularly in the petroleum and petrochemical industries. It is commonly employed in processes such as desulfurization, oxidation, and hydrodesulfurization.

2. Fertilizers: Ammonium dimolybdate is used as a source of molybdenum in fertilizers. Molybdenum is an essential micronutrient for plants, and its deficiency can adversely affect crop growth and development. Adding ammonium dimolybdate to the soil helps provide plants with the required molybdenum.

3. Pigments: Ammonium dimolybdate is used in the production of pigments, specifically yellow and orange pigments. These pigments find applications in various industries, including paints, ceramics, plastics, and textiles.

4. Corrosion inhibitors: Ammonium dimolybdate is utilized as a corrosion inhibitor in various systems, such as cooling water treatment, metal surface coatings, and oil and gas pipelines. It helps to prevent or slow down the corrosion process by forming a protective film on the metal surface.

5. Analytical chemistry: Ammonium dimolybdate is used as a reagent in analytical chemistry, particularly for the determination of phosphates and silicates. It forms complexes with these analytes, allowing their quantification through colorimetric or spectrophotometric methods.

6. Electroplating: Ammonium dimolybdate is sometimes used in the electroplating industry for molybdenum plating. This process can enhance the corrosion resistance and wear resistance of metal surfaces.

7. Research and development: Ammonium dimolybdate is employed in various research and development activities, such as the synthesis of other molybdenum compounds, the preparation of catalysts, and the investigation of new chemical reactions and processes.