Sodium pyrophosphate is a white or yellow crystalline powder or small crystal, with sulfurous acid odor, the proportion of 1.4, soluble in water, aqueous solution is acidic, and strong acid contact with the release of sulfur dioxide and the formation of the corresponding salts. Sodium pyrophosphate can not be stored for a long time, and the packaging should be sealed to prevent air oxidation. Soluble in water soluble in glycerin, slightly soluble in ethanol. Moisture easily decomposed, exposed to the air easily oxidized into sodium sulfate.