Trisodium Phosphate – an inorganic compound

Trisodium Phosphate – an inorganic compound

Trisodium phosphate (TSP) is a compound with the chemical formula Na3PO4. It is a white, granular or crystalline solid that is highly soluble in water. It is an inorganic compound. It is a white, granular or crystalline solid, highly soluble in water, producing an alkaline solution. The item of commerce is often partially hydrated and may range from anhydrous Na3PO4 to the dodecahydrate Na3PO4 · 12 H2O. Most often found in white powder form, it can also be called trisodium orthophosphate or simply sodium phosphate.

TSP is used as a cleaning agent, builder, lubricant, food additive, stain remover, and degreaser. It is often used in various industrial and household applications due to its properties as a strong cleaning agent, water softener, and food additive.


  • Chemical formula: Na3PO4
  • Molar mass: 163.939 g·mol−1
  • Density: 2.536 g/cm3 (17.5 °C, anhydrous); 1.62 g/cm3 (20 °C, dodecahydrate)
  • Melting point: 1,583 °C (2,881 °F; 1,856 K) (anhydrous); 73.4 °C (164.1 °F; 346.5 K) (dodecahydrate)
  • Boiling point: 100 °C (212 °F; 373 K) (dodecahydrate) decomposes
  • Solubility in water: anhydrous: 5.4 g/100 mL (0 °C); 94.6 g/100 mL (100 °C)
  • dodecahydrate: 28.3 g/100 mL (20 °C)
  • Solubility: insoluble in ethanol
  • Crystal structure: Trigonal


Trisodium phosphate is produced by neutralization of phosphoric acid using sodium carbonate, which produces disodium hydrogen phosphate. The disodium hydrogen phosphate is reacted with sodium hydroxide to form trisodium phosphate and water.

Na2CO3 + H3PO4 → Na2HPO4 + CO2 + H2O

Na2HPO4 + NaOH → Na3PO4 + H2O


TSP is used in a variety of industrial and household applications, including as a cleaning agent, a food additive, a stain remover, and a water softener. In food, TSP is used as an emulsifier and a thickening agent, and it is commonly found in processed cheeses and baked goods. However, TSP can be toxic if ingested in large quantities and can cause skin and eye irritation upon contact. As such, it is important to handle TSP with care and follow appropriate safety precautions.

In industrial settings, TSP is commonly used as a degreaser, cleaning agent, and stain remover. It is also used as a water softener to prevent the build-up of scale and deposits in pipes and other equipment.

Health hazards

It’s important to note that while TSP can be effective in certain applications, it can also be harmful to the environment and human health if not used or disposed of properly. As with all chemicals, it is important to use TSP in accordance with safety guidelines and to dispose of it appropriately to minimize any negative impact on the environment.