Substance profile
Sodium metabisulphite
Sodium metabisulphite is white hexagonal crystals or powder with an in the presences of traces of water, it develops an odor of sulfur dioxide.
01 · Identification
What Sodium metabisulphite is
Sodium metabisulphite is white hexagonal crystals or powder with an in the presences of traces of water, it develops an odor of sulfur dioxide. Its molecular formula is Na2O5S2 and its molecular weight is 190.11 g/mol. It melts at 150 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H302 | Harmful if swallowed. |
| H318 | Causes serious eye damage. |
Supplemental EU statements: EUH031
Precautionary statements: P270, P280, P301, P305, P310, P312, P330, P338
03 · Physical and chemical properties
Sodium metabisulphite properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | Decomposes | decomposes | NIOSH |
| Decomposes (NIOSH, 2024) | decomposes | CAMEO | |
| decomposes | decomposes | OSHA | |
| Melting point | 150 °C (302 °F) | above this value | HSDB |
| Density | 1.4 g/cm³ | NIOSH | |
| 1.4 g/cm³ | at 25 °C | HSDB | |
| Solubility | Freely soluble in water, glycerol; slightly soluble in alcohol | HSDB | |
| Soluble in ethanol | HSDB | ||
| 66.7 g/100 g water at 25 °C | at 25 °C | HSDB | |
| Lower explosive limit (LEL) | Noncombustible Solid | NIOSH |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Sodium metabisulphite
Storage conditions
The bulk material should be stored in a well closed container, protected from light, in a cool, dry place.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Large scale addition of solid sodium disulfite to an unstirred and too-concentrated solution of sodium nitrite caused a vigorous exothermic reaction.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
SODIUM METABISULFITE is incompatible with the following: Heat (decomposes) [Note: Slowly oxidized to the sulfate on exposure to air & moisture.] (NIOSH, 2024).
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Sodium metabisulphite in the storage compatibility matrix →