Substance profile
Sodium Dithionite
Sodium Dithionite is a white or grayish-white crystalline powder with a faint sulfurous odor.
01 · Identification
What Sodium Dithionite is
Sodium Dithionite is a white or grayish-white crystalline powder with a faint sulfurous odor. It melts at 52 °C.
Under the GHS it carries the signal word Danger. It is classed as reactive agents - 2nd degree.
Other names for Sodium Dithionite
- sodium hydrosulphite
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 |
|---|---|
| H251 | Self-heating: may catch fire. |
| H302 | Harmful if swallowed. |
Supplemental EU statements: EUH031
03 · Physical and chemical properties
Sodium Dithionite 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 |
|---|---|---|---|
| Melting point | 52 °C (125.6 °F) | decomposes, decomposes | HSDB |
| Density | 2.38 g/cm³ | HSDB | |
| 1.58 g/cm³ | Dihydrate | HSDB | |
| 2.4 g/cm³ | ICSC | ||
| Solubility | Slightly sol in alcohol; very soluble in water | HSDB | |
| Slightly sol in cold water; insoluble in acids | HSDB | ||
| At 20 °C, 24.1 g/100 g water | at 20 °C | HSDB | |
| Flash point | 100 °C (212 °F) | approximate, open cup | HSDB |
| 100 °C (212 °F) | above this value | ICSC | |
| Autoignition temperature | 190 °C (374 °F) | approximate | HSDB |
| Lower explosive limit (LEL) | Combustible solid but not explosive. | HSDB | |
| Closed containers may rupture violently when heated. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Sodium Dithionite
Storage conditions
Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Do not store near acids. Air sensitive. Heat sensitive. Moisture sensitive. Handle under inert gas. Protect from moisture.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Use of scoop contaminated with sodium dithionite for sodium chlorite caused ignition of latter. Material containing sulfur (dithionite, natural rubber gloves) cause decomp of sodium chlorite and contact should be avoided.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
Sodium dithionite is a combustible solid which slowly decomposes when in contact with water or water vapor, forming thiosulfates and bisulfites. This reaction evolves heat, which can further accelerate the reaction or cause surrounding materials to burn. If the mixture is confined, the decomposition reaction can result in pressurization of the container which may then rupture forcefully. Upon standing in air it slowly oxidizes, generating toxic sulfur dioxide gas. (NFPA, 2010)
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Sodium Dithionite in the storage compatibility matrix →