Trisodium phosphate dodecahydrate
[CAS# 10101-89-0]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Phosphides, metal phosphoric acid, metaphosphoric acid, hypophosphorous acid and pyrophosphate
• Name: Trisodium phosphate dodecahydrate
• Synonyms: Sodium phosphate dodecahydrate
• Molecular Formula: Na₃PO₄.12(H₂O)
• Molecular Weight: 380.12
• CAS Registry Number: 10101-89-0
• EC Number: 600-151-8
• SMILES: O.O.O.O.O.O.O.O.O.O.O.O.[O-]P(=O)([O-])[O-].[Na+].[Na+].[Na+]

Properties

• Density: 1.62
• Melting point: 75 °C
• Water solubility: 258 g/L (20 °C)

Safety Data

• Hazard Symbols: CGHS05;GHS07 Danger
• Risk Statements: H314-H315-H318-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-P317-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
Skin corrosion	Skin Corr.	1B	H314
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1	H314
Skin corrosion	Skin Corr.	1C	H314
Eye irritation	Eye Irrit.	2A	H319

• Transport Information: UN 9148; UN 3262

Discovery and Applications

Trisodium phosphate dodecahydrate (Na3PO4·12H2O) was synthesized in the late 19th century during investigations into phosphate compounds. By reacting sodium carbonate with phosphoric acid, chemists produced trisodium phosphate, which crystallized in its stable dodecahydrate form. This compound’s solubility and chemical properties have since led to its widespread use in various applications.

Trisodium phosphate dodecahydrate is an effective cleaning agent in industrial and household settings. Its strong alkaline nature makes it suitable for removing grease, oils, and heavy grime from surfaces such as walls and floors. It is used to clean and prepare surfaces for painting and in degreasing machinery and equipment in industrial environments.

This compound is used in water treatment to control acidity and stabilize pH levels. It helps prevent corrosion in pipes and equipment and reduces water hardness by precipitating calcium and magnesium ions. This makes it beneficial for boilers and cooling systems, improving efficiency and extending equipment life by minimizing scale buildup.

In food processing, trisodium phosphate dodecahydrate acts as an emulsifier, buffering agent, and preservative. It stabilizes the texture of cheeses, meats, and baked goods, prevents separation of oils and water in cheese production, and maintains pH in processed foods and beverages. Its emulsifying properties enhance the stability and consistency of sauces, dressings, and processed foods.

Trisodium phosphate dodecahydrate is used in pharmaceuticals to maintain stable pH levels in oral and injectable formulations, ensuring drug stability and efficacy. It serves as a buffering agent in various medications and is a reagent in laboratory analyses and buffer solutions for biological and chemical research.

In agriculture, trisodium phosphate dodecahydrate is a nutrient supplement in fertilizers, providing phosphorus to support plant growth. It enhances root development and nutrient uptake, aids in soil remediation, and is used in hydroponic systems to maintain balanced nutrient solutions for healthy plant growth.

The compound is also used as a flame retardant. When applied to combustible materials, it forms a non-combustible layer, preventing the spread of fire and protecting buildings and other materials from fire damage.

References

2003. Monitoring dehydration and condensation processes of Na2HPO4 · 12H2O using thermo-Raman spectroscopy. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 59(7).
DOI: 10.1016/S1386-1425(02)00395-5

2005. Effectiveness of Trisodium Phosphate Treatment against Pathogenic and Spoilage Bacteria on Poultry during Refrigerated Storage. Journal of Food Protection, 68(4).
DOI: 10.4315/0362-028X-68.4.866