Ammonium Dihydrogen Phosphate (ADP), with the chemical formula **NH?H?PO?**, is an important inorganic compound widely used in agriculture, industry, and scientific research. Below is its key information:

1. Basic Properties

- Physical Properties: White crystalline powder or granules, highly soluble in water, with an aqueous solution that is weakly acidic (pH around 4.5).

- Chemical Properties:

  - Decomposes when heated above 190°C, producing ammonia (NH?) and phosphoric acid (H?PO?).

  - Reacts with bases to form ammonium phosphate or other phosphates.

2. Main Applications

- Agriculture: A high-phosphorus, high-nitrogen compound fertilizer suitable for phosphorus-deficient soils, promoting crop growth.

- Industry:

  - Flame Retardant: Used in plastics, wood, and textiles, functioning by endothermic decomposition and the release of flame-retardant gases.

- Food Additive: Acts as a leavening agent or acidity regulator.

- Scientific Research: Used in the preparation of nonlinear optical crystals for laser technology.

- Others: Pharmaceuticals, water treatment (as a corrosion inhibitor), and fire extinguisher components.

4. Safety Precautions

- Irritancy: Dust may irritate the eyes, skin, and respiratory tract; protective equipment should be worn during handling.

- Environmental Risks: Excessive discharge may lead to water eutrophication.

- Storage: Keep sealed in a cool, dry place, away from strong bases and high temperatures.