Ammonium dihydrogen phosphate
[CAS# 7722-76-1]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Phosphides, metal phosphoric acid, metaphosphoric acid, hypophosphorous acid and pyrophosphate
• Name: Ammonium dihydrogen phosphate
• Synonyms: Ammonium phosphate; Ammonium phosphate monobasic
• Molecular Formula: NH₄H₂PO₄
• Molecular Weight: 115.03
• CAS Registry Number: 7722-76-1
• EC Number: 231-764-5
• SMILES: [NH4+].OP(=O)(O)[O-]

Properties

• Density: 1.803
• Melting point: 190 °C
• Water solubility: 368 g/L (20 °C)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335-H412
• Safety Statements: P261-P264-P264+P265-P271-P273-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Eye irritation	Eye Irrit.	2B	H320
Skin mild irritation	Skin Mild Irrit. 99	3	H316
Specific target organ toxicity - single exposure	STOT SE	3	H336

Discovery and Applications

Diammonium phosphate, also known as ADP, was first synthesized in the 19th century as part of an effort to develop effective fertilizers. It is a crystalline solid composed of ammonium (NH4?) and dihydrogen phosphate (H2PO4?) ions. This compound combines the fertilizing properties of nitrogen (in the form of ammonium) and phosphorus (in the form of phosphate), making it valuable for plant nutrition. It is typically produced by reacting phosphoric acid with ammonia.

Diammonium phosphate is a key ingredient in fertilizers. Its high phosphorus content makes it particularly valuable in promoting plant root development, flowering, and fruiting. Ammonium nitrogen is easily absorbed by plants, which improves overall growth and productivity. ADP is commonly used as a granular or water-soluble fertilizer in a variety of agricultural settings, from large-scale agriculture to home gardening. In addition to its use as a fertilizer, diammonium phosphate is also used as a soil conditioner. It helps correct phosphorus deficiencies in the soil and improves soil fertility and structure. This helps improve nutrient availability and uptake by plants, resulting in healthier crops and higher yields.

Ammonium dihydrogen phosphate is widely used in dry powder fire extinguishers, especially those designed for Class A, B, and C fires involving common combustibles, flammable liquids, and electrical equipment. When heated, ADP decomposes to release phosphoric acid and ammonia, which helps suppress flames and reduce combustion. This makes it an effective agent for extinguishing a variety of fires. In addition to fire extinguishers, ADP is used as a flame retardant for treating textiles, paper, and other combustible materials. It forms a protective barrier and reduces flammability, helping to improve fire safety in a variety of applications. Ammonium dihydrogen phosphate is used in the electroplating industry, where it acts as a buffer and provides phosphate ions in the plating solution. This application helps ensure uniform deposition of metal coatings on a variety of substrates, thereby improving the quality and durability of the plated products. In the food industry, ammonium dihydrogen phosphate is used as a food additive and as a leavening agent, acidity regulator, and nutritional supplement in yeast-fermented products. Its role in enhancing the texture and stability of baked goods and other foods shows its usefulness in food processing.

In the pyrotechnics industry, ammonium dihydrogen phosphate is used as an ingredient in certain types of fireworks and pyrotechnic devices. It produces a bright flame and acts as a stabilizer, helping to create colorful and safe pyrotechnic effects. In the laboratory, ammonium dihydrogen phosphate is used as a reagent in various chemical analyses and experiments. Its solubility and reactivity make it useful in preparing buffer solutions, studying plant nutrition, and conducting inorganic chemistry research.

References

2014. Chemical fertilizers as a source of (238)U, (40)K, (226)Ra, (222)Rn, and trace metal pollutant of the environment in Saudi Arabia. Environmental Science and Pollution Research International, 22(11).
DOI: 10.1007/s11356-014-3984-3

2013. Supplementation of medium with diammonium hydrogen phosphate enhanced the d-lactate dehydrogenase levels leading to increased d-lactic acid productivity. Bioresource Technology, 146.
DOI: 10.1016/j.biortech.2013.07.057

2003. Transcriptional profiling of wine yeast in fermenting grape juice: regulatory effect of diammonium phosphate. FEMS Yeast Research, 3(3).
DOI: 10.1016/s1567-1356(02)00201-5