Sodium Dithionite is the same as Sodium hydrosulfite CAS N°: 7775-14-6. Formula Na₂S₂O₄
This is a strong reducing agent for indigo vats.
The difference for this powder is that it does not have the strong sulfur smell that comes with traditional sodium hydrosulfit.
 
For use in an indigo vat I usually use the formula of 5 grams indigo, 5 grams of sodium diothonite and 12 grams of soda ash per liter water. You multiply this per the number of liters you want your vat to be.
 
This powder is packed in a 500 grams in a double plastic ziplock bag.
 
 
Key Spec Table
CAS #EC NumberHill FormulaChemical FormulaMolar Mass7775-14-6231-890-0Na₂O₄S₂Na₂S₂O₄174.11 g/mol 
DescriptionCatalogue Number106505SynonymsSodium hydrosulfite, Sodium hypodisulfiteProduct InformationCAS number7775-14-6EC index number016-028-00-1EC number231-890-0Hill FormulaNa₂O₄S₂Chemical formulaNa₂S₂O₄Molar Mass174.11 g/molHS Code2831 10 00Quality LevelMQ200Physicochemical InformationDensity2.5 g/cm3 (20 °C)Flash point>100 °CIgnition temperature>200 °CMelting Point100 °C (decomposition)pH value5.5 - 8.5 (50 g/l, H₂O, 20 °C)Bulk density1250 kg/m3Solubility250 g/l (slow decomposition)Storage and Shipping InformationStorageStore at +2°C to +30°C.