Na2HPO4

Na2HPO4, commonly called disodium hydrogen phosphate, is an inorganic salt with the formula Na2HPO4. It appears as a white, odorless solid and occurs in several hydrated forms as well as the anhydrous salt. It is highly soluble in water.

Chemically, Na2HPO4 is the dibasic salt of phosphoric acid (H3PO4) and acts as a buffering and sequestering agent. In solution it yields the HPO4^2− anion, which gives the solution a basic character. Its buffering capacity is most commonly utilized in phosphate buffers, in combination with NaH2PO4 to cover pH ranges around neutrality to moderately alkaline. It is a component of many laboratory buffers and food-grade phosphate systems.

Uses: In food processing, disodium phosphate serves as a buffering agent, emulsifier, and sequestrant in products such as processed cheese and processed meats. In the chemical and industrial sectors it is used in water treatment as a corrosion inhibitor and scale control agent, and in detergents and cleaners as a water-softening ingredient. It also appears in some cosmetics and pharmaceutical formulations as a buffering or excipient.

Safety: Na2HPO4 is of low acute toxicity but can irritate the eyes, skin, and respiratory tract in dusty or concentrated form. It should be handled with appropriate precautions, stored in a cool, dry place, and kept away from incompatible materials.