Sodium pyrosulfate is an inorganic compound with the chemical formula of Na2S2O7.

[1] It is a colorless salt.

[3] It hydrolyses in water to form sodium bisulfate with a chemical formula of NaHSO4 which has a pH of around 1.

Sodium pyrosulfate is obtained by heating sodium bisulfate to 280 °C (536 °F) [4][5] Temperatures above 460 °C further decompose the compound, producing sodium sulfate and sulfur trioxide: Sodium pyrosulfate was used in analytical chemistry.

Samples are fused with sodium pyrosulfate to ensure complete dissolution before a quantitative analysis.