sodium thiosulfate anhydrous, (Na2S2O3) can be synthesized from sodium sulfate.Sodium thiosulfate is an inorganic sodium salt composed of sodium and thiosulfate ions in a 2:1 ratio. It has a role as an antidote to cyanide poisoning, a nephroprotective agent and an antifungal drug.It can be obtained from Na2S2O3.10H2O by heating above 100°C.