Substance profile
Sulfur Dioxide
Sulfur Dioxide is a colorless gas or liquid with a strong suffocating odor.
01 · Identification
What Sulfur Dioxide is
Sulfur Dioxide is a colorless gas or liquid with a strong suffocating odor. It boils at -10 °C, melts at -75.5 °C.
Under the GHS it carries the signal word Danger.
Other names for Sulfur Dioxide
- sulphur dioxide
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 |
|---|---|
| H331 | Toxic if inhaled. |
| H370 | Causes damage to organs <or state all organs affected, if known> <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H314 | Causes severe skin burns and eye damage. |
Precautionary statements: P260, P271, P280, P301, P304, P310, P331
03 · Physical and chemical properties
Sulfur Dioxide 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 | -10.05 °C (13.9 °F) | HSDB | |
| -10 °C (14 °F) | NIOSH | ||
| -10 °C (14 °F) | at 760 mmHg | CAMEO | |
| Melting point | -75.5 °C (-103.9 °F) | HSDB | |
| -75.56 °C (-104 °F) | NIOSH | ||
| -72.72 °C (-98.9 °F) | CAMEO | ||
| Density | 0.0026 g/cm³ | HSDB | |
| 1.5 g/cm³ | liquid | HSDB | |
| 1.434 g/cm³ | CAMEO | ||
| Solubility | Soluble in water | HSDB | |
| Soluble in water ... forms sulfurous acid (H2SO3) | HSDB | ||
| In water, 1.07X10+5 mg/L at 21 °C | at 21 °C | HSDB | |
| Vapor pressure | 2432 mmHg | NIOSH | |
| 2432 mmHg | at 20 °C | CAMEO | |
| 2475 mmHg | at 20 °C | ICSC | |
| Autoignition temperature | Not flammable (USCG, 1999) | CAMEO | |
| Lower explosive limit (LEL) | Nonflammable Gas | NIOSH | |
| Vapor density | 2.26 (air = 1) | CAMEO | |
| 2.25 (air = 1) | ICSC | ||
| Odor threshold | 4.70X10-1 ppm (recognition in air, chemically pure) | HSDB | |
| Odor threshold: 0.1 ppm (low); 3.0 ppm (high) | HSDB | ||
| Odor threshold: 1.1750 mg/cu m (low); 12.5000 mg/cu m (high); Irritating odor concn: 5.0 mg/cu m. | HSDB | ||
| Critical temperature and pressure | 157.49 °C (315.5 °F) | HSDB | |
| Corrosivity | Liquid sulfur dioxide will attack some forms of plastic, rubber, and coatings | HSDB | |
| Corrodes aluminum | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Source notes
Further notes on Sulfur Dioxide
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Corrosivity
Iron, steel, nickel, copper-nickel alloys, & inconel nickel-chromium-iron are satisfactory for dry or hot sulfur dioxide, but they are readily corroded below the dew point or by wet sulfur dioxide gas. Liquid sulfur dioxide produces serious corrosion of iron, brass, and copper at about 0.2 wt% or higher moisture content.
Source: HSDB
05 · Handling and storage
Storing and handling Sulfur Dioxide
Storage conditions
Storage temp: less than 130 °F
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Will react with water or steam to produce toxic and corrosive fumes.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Sulfur Dioxide in the storage compatibility matrix →