Sodium dihydrogen phosphate dihydrate, also known as monosodium phosphate dihydrate or NaH2PO4.2H2O, is a crystalline, odorless, and colorless compound. It is a white, hygroscopic powder that is soluble in water but insoluble in alcohol. It is commonly used in the food industry as a buffering agent, emulsifier, and thickening agent, as well as in the production of fertilizers, detergents, and other industrial applications.

Sodium dihydrogen phosphate dihydrate is a source of both sodium and phosphate ions, which are essential nutrients for plants and animals. It is also used in the preparation of various chemical reagents and as a pH regulator in laboratory applications. It has a molecular weight of 156.01 g/mol and a density of 1.915 g/cm³.

While generally considered safe for consumption in small quantities, excessive intake of sodium dihydrogen phosphate dihydrate can lead to health issues such as nausea, vomiting, diarrhea, and abdominal pain. As with any chemical compound, it should be handled and used with caution and in accordance with proper safety procedures.