Sodium metabisulfite

CAS 7681-57-4Na2O5S2MW 189.90 g/mol

Sodium metabisulfite (CAS 7681-57-4) — formula Na2O5S2, molecular weight 189.90 g/mol; category fine chemicals.

Product Overview

CAS Number	7681-57-4
Molecular Formula	Na2O5S2
Molecular Weight	189.90 g/mol
Category	Bleaching Agents\|Basic Chemical Raw Materials

Technical Profile

What this product is

Sodium metabisulfite is a high-value fine compound with CAS registry number 7681-57-4 and molecular formula Na2O5S2 (molecular weight 189.90 g/mol), belonging to the fine chemicals segment of chemical raw materials.

Identification

CAS number: 7681-57-4

Its molecular formula Na2O5S2 comprises 2 Na, 5 O, 2 S atoms.

Also known as: Sodium metabisulfite

Category: chemical / fine chemicals

Frequently Asked Questions

What is the CAS number of Sodium metabisulfite?

The CAS registry number of Sodium metabisulfite is 7681-57-4.

What is the molecular formula and molecular weight of Sodium metabisulfite?

Molecular formula Na2O5S2, molecular weight 189.90 g/mol.

What other names is Sodium metabisulfite known by?

It is also registered under: Sodium metabisulfite.

Which category does Sodium metabisulfite belong to?

Category: Bleaching Agents / Basic Chemical Raw Materials.

PubChem Public Data

Independent reference data for Sodium metabisulfite (CAS 7681-57-4), compiled from public chemistry databases.

Registry identifiers across databases

CAS Registry Number	7681-57-4
PubChem CID	656671
Molecular formula	Na2S2O5
UNII (FDA)	4VON5FNS3C

Computed descriptors

Molecular Weight	190.11
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	0
Exact Mass	189.89825401
Monoisotopic Mass	189.89825401
Topological Polar Surface Area	125
Heavy Atom Count	9

Physicochemical values on record

Solubility	54 % (NIOSH, 2024)
Solubility	66.7 g/100 g water at 25 °C
Solubility	54%
Density	2.36 g/cm³
Density	1.4
Density	1.4 @25 °C
LogP	-3.7
Decomposition	150 °C
pH	4,0-5,5 (10 % aqueous solution)

Documented uses on record

Synonyms and trade names

Sodium metabisulfite; 7681-57-4; Sodium pyrosulfite; Sodium disulfite; Disodium pyrosulfite; Natrii disulfis; Campden Tablets; Disodium metabisulfite; Natrium pyrosulfit; Natriummetabisulfit; sodium pyrosulphite; Sodium bisulfite anhydrous; Natrium metabisulfurosum; Sodium pyrosulfite (Na2S2O5); Disodium pentaoxodisulfate; 4VON5FNS3C

Regulatory listings held on file

Regulatory & Food Contact	FDA Substance added to food: ANTIMICROBIAL AGENT, ANTIOXIDANT, COLOR OR COLORING ADJUNCT, DOUGH STRENGTHENER, ANTIOXIDANT; FLOUR_TREATMENT_AGENT; PRESERVATIVE: Food Additives ANTIMICROBIAL AGENT, ANTIOXIDANT, COLOR OR COLORING ADJUNCT, DOUGH STRENGTHENER, FLOUR TREATING AGENT, FREEZIN JECFA ADI: 0-0.7 mg/kg bw TRS 891-JECFA 51/30 FAS 42-JECFA 51/95
GHS notification summary	0.4% (11 / 3060)

GHS hazard classification

GHS notification summary	0.4% (11 / 3060)
Reported hazard statements	H302, H318, H317, H334, H335, H402, H412, H320

H302: Harmful if swallowed [Warning Acute toxicity, oral]

H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]

What the public record says

Sodium Metabisulphite Food Grade · CAS 7681-57-4 · Na2S2O5. UNII 4VON5FNS3C. Solubility: 54 % (NIOSH, 2024); Solubility: 66.7 g/100 g water at 25 °C; Solubility: 54%.

Physical description and handling notes

Source: PubChem / Wikidata; the batch COA governs where values differ.