Substance profile
Pyridine
Pyridine is a colorless to yellow liquid with a sharp, nauseating odor.
01 · Identification
What Pyridine is
Pyridine is a colorless to yellow liquid with a sharp, nauseating odor. Its molecular formula is C5H5N and its molecular weight is 79.1 g/mol. It boils at 116 °C, melts at -41.6 °C, is miscible with water.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 3rd degree.
Other names for Pyridine
- Azabenzene
- Azine
- Cp 32
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 |
|---|---|
| H225 | Highly flammable liquid and vapour. |
| H332 | Harmful if inhaled. |
| H312 | Harmful in contact with skin. |
| H302 | Harmful if swallowed. |
Precautionary statements: P210, P233, P241, P242, P260, P270, P271, P280, P301, P302, P304, P312, P330, P352, P403
03 · Physical and chemical properties
Pyridine 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 | 115.56 °C (240 °F) | NIOSH | |
| 115 °C (239 °F) | at 760 mmHg | CAMEO | |
| 115 °C (239 °F) | ICSC | ||
| Melting point | -41.6 °C (-42.9 °F) | HSDB | |
| -42.22 °C (-44 °F) | NIOSH | ||
| Density | 0.98 g/cm³ | NIOSH | |
| 0.9827 g/cm³ | at 20 °C | HSDB | |
| 0.983 g/cm³ | at 20 °C | CAMEO | |
| Solubility | Miscible with ... alcohol, ether, and petroleum ether, oils and many organic liquids. | HSDB | |
| Miscible | NIOSH | ||
| Miscible with water @ 20 °C | at 20 °C | HSDB | |
| Vapor pressure | 16 mmHg | NIOSH | |
| 18 mmHg | at 20 °C | CAMEO | |
| 20.8 mmHg | at 25 °C | HSDB | |
| Flash point | 20 °C (68 °F) | HSDB | |
| 20 °C (68 °F) | closed cup | HSDB | |
| Autoignition temperature | 482 °C (899.6 °F) | HSDB | |
| 482.22 °C (900 °F) | CAMEO | ||
| Lower explosive limit (LEL) | 1.8 % by volume | HSDB | |
| Upper explosive limit (UEL) | 12.4 % by volume | HSDB | |
| Vapor density | 0.982 (air = 1) | HSDB | |
| 2.72 (air = 1) | CAMEO | ||
| 2.73 (air = 1) | ICSC | ||
| Odor threshold | Water odor threshold: 0.95 mg/l; Air odor threshold: 0.17 ul/l; Odor safety class: B. B= 50-90% of distracted persons perceive warning of TLV. | HSDB | |
| Odor detection in water is 8.20x10+1 ppm; chemically pure | HSDB | ||
| Odor recognition in air is 2.10x10-2 ppm; chemically pure | HSDB | ||
| Critical temperature and pressure | 346.78 °C (656.2 °F) | HSDB | |
| Corrosivity | Liquid pyridine will attack some forms of plastics, rubber and coatings. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Pyridine
Storage conditions
OUTSIDE OR DETACHED STORAGE IS PREFERABLE. ISOLATE FROM POWERFUL OXIDIZING MATERIALS AND ACIDS.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
PYRIDINE REACTS VIOLENTLY WITH CHLOROSULFONIC ACID, CHROMIC ACID, MALEIC ANHYDRIDE, NITRIC ACID, FUMING SULFURIC ACID, PERCHROMATES, BETA-PROPIOLACTONE, SILVER PERCHLORATE, & SULFURIC ACID.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Pyridine in the storage compatibility matrix →
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