Diammonium hydrogenphosphate
[CAS# 7783-28-0]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Phosphides, metal phosphoric acid, metaphosphoric acid, hypophosphorous acid and pyrophosphate
• Name: Diammonium hydrogenphosphate
• Synonyms: Diammonium hydrogenorthophosphate; Ammonium hydrogen phosphate
• Molecular Formula: (NH₄)₂.HPO₄
• Molecular Weight: 132.06
• CAS Registry Number: 7783-28-0
• EC Number: 231-987-8
• SMILES: [NH4+].[NH4+].OP(=O)([O-])[O-]

Properties

• Density: 1.619 g/mL
• Melting point: 155 °C (decomp.)
• Water solubility: 58 g/100mL (10 °C)

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H314-H315-H319-H335
• Safety Statements: P260-P261-P264-P264+P265-P271-P280-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P351+P338-P305+P354+P338-P316-P319-P321-P332+P317-P337+P317-P362+P364-P363-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
Acute toxicity	Acute Tox.	4	H312
Acute toxicity	Acute Tox.	4	H332
Eye irritation	Eye Irrit.	2B	H320
Skin mild irritation	Skin Mild Irrit. 99	3	H316
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412

Discovery and Applications

Diammonium Hydrogen Phosphate (chemical formula (NH4)2HPO4), also known as diammonium phosphate (DAP), was first synthesized and identified in the field of chemistry and is recognized for its convenient source of ammonium and phosphate ions. It is composed of two ammonium ions (NH4?) and one hydrogen phosphate ion (HPO4²?). This composition makes it highly soluble in water, facilitating its use in a variety of applications.

Diammonium phosphate is primarily used as a high-phosphorus fertilizer in agriculture. It provides plants with essential nutrients—phosphorus and nitrogen—to promote healthy root development, vigorous growth, and increased crop yields. Its water solubility ensures rapid nutrient uptake by plants, making it effective in both soil applications and irrigation systems. Due to its balanced nitrogen-to-phosphorus ratio, diammonium phosphate is often used as a starter fertilizer for crops that require an early nutrient supply. It supports seedling establishment and early plant growth and is particularly useful in nutrient-deficient soils or during critical growth stages.

In the food industry, diammonium phosphate is used as a leavening agent in baking powder. It releases carbon dioxide gas when exposed to moisture and heat, causing dough to rise, resulting in light, fluffy baked goods. Its stable chemistry ensures consistent baking performance.

Diammonium phosphate is used as a flame retardant in a variety of applications, including textiles, wood products, and plastics. It inhibits combustion by releasing ammonia and phosphoric acid vapors, which dilute the flammable gases and suppress the chemical chain reaction of fire.

When used properly, diammonium phosphate has a low impact on the environment. However, its use in agriculture requires proper management to prevent nutrient loss and minimize potential impacts on water quality and ecosystems. Adherence to recommended application rates and operations ensures sustainable use and environmental stewardship.

Research on diammonium phosphate focuses on improving nutrient efficiency, reducing environmental impact, and exploring its potential in sustainable agricultural practices. Innovations are aimed at enhancing its formulations, developing controlled-release technologies, and optimizing its use in precision agriculture for tailored nutrient management.

References

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

2016. Improvement in lipids extraction processes for biodiesel production from wet microalgal pellets grown on diammonium phosphate and sodium bicarbonate combinations. Bioresource Technology, 214.
DOI: 10.1016/j.biortech.2016.04.036

2007. Online estimation of assimilable nitrogen by electrical conductivity measurement during alcoholic fermentation in enological conditions. Journal of Bioscience and Bioengineering, 103(3).
DOI: 10.1263/jbb.103.229