Use
Sodium thiosulfate has two forms as anhydrous sodium thiosulfate (Na2S2O3) and sodium thiosulfate pentahydrate (Na2S2O3 · 5H2O), the latter is also known as soda and Hyperion. A molecular weight is 158.11 and 248.18 respectively. Anhydrous sodium thiosulfate is an opaque crystalline powder. The relative density is 1.667. It is odorless, salty taste, soluble in water, insoluble in ethanol. It decomposes in acidic solution, has a strong reduction, easily absorbs moisture. Sodium thiosulfate pentahydrate is odorless, colorless and transparent monoclinic crystals or granules. The relative density is 1.685. The melting point is 48 ℃. It loses all crystal water at 100 ℃, and decomposes above 100 ℃. It is easily weathered in dry and hot air, slightly deliquescence in the hot and humid air. It is soluble in water and turpentine, insoluble in ethanol, decomposes in case of strong acid. Prolonged exposure in the air, it is easily oxidated and carbonized by oxygen and carbon dioxide.