White powder or crystals. The relative density of 2.534, melting point 880 ℃, boiling point of 938 ℃. Colorless or white crystalline powder. soluble in water,

Solubility in water at 20 ℃ 100g for 6.23, its aqueous solution is alkaline; insoluble in alcohol. Solution is still stable below 70 ℃, boiling the hydrolysis

As disodium hydrogen phosphate. In dry air weathering, lose crystal water at 100 ℃. In the air easily absorb moisture and deliquescence. With an alkaline earth metal ion

Can form a complex; and Ag + is generated when white pyrophosphate silver met.