8638. Sodium Metabisulfite

Nomenclature

CAS number: 7681-57-4
Disulfurous acid sodium salt (1:2).
Na2O5S2; mol wt 190.11.
Na 24.19%, O 42.08%, S 33.73%.
Na2S2O5.

Description and references

Crystal structure: K. L. Carter et al., Acta Crystallogr. B60, 155 (2004).

Properties

White crystals or powder; odor of SO2. d 2.34-2.36. Freely sol in water, glycerol; slightly sol in alcohol. The aq soln is acid.

Caution

Potential symptoms of overexposure are irritation of eyes, skin and mucous membranes. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 284.

Use

Pharmaceutic aid (antioxidant). Reducing agent.