Substance profile
Phosgene
Phosgene is a colorless gas with a suffocating odor; when diluted with air there is an odor reminiscent of moldy.
01 · Identification
What Phosgene is
Phosgene is a colorless gas with a suffocating odor; when diluted with air there is an odor reminiscent of moldy. Its molecular formula is CCl2O and its molecular weight is 98.91 g/mol. It boils at 8.2 °C, melts at -118 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
Other names for Phosgene
- carbonyl chloride
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 |
|---|---|
| H330 | Fatal if inhaled. |
| H314 | Causes severe skin burns and eye damage. |
Precautionary statements: P260, P271, P280, P301, P304, P310, P331
03 · Physical and chemical properties
Phosgene 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 | 8.2 °C (46.8 °F) | at 760 mmHg | HSDB |
| 8.33 °C (47 °F) | NIOSH | ||
| 8.33 °C (47 °F) | at 760 mmHg | CAMEO | |
| Melting point | -118 °C (-180.4 °F) | HSDB | |
| -127.78 °C (-198 °F) | NIOSH | ||
| -117.78 °C (-180 °F) | CAMEO | ||
| Density | 0.52 g/cm³ | HSDB | |
| 1.4 g/cm³ | ICSC | ||
| 1.3719 g/cm³ | at 25 °C | HSDB | |
| Solubility | Slightly sol in water; freely sol in benzene, toluene, glacial acetic acid, and most liquid hydrocarbons | HSDB | |
| Soluble in benzene, carbon tetrachloride, chloroform, toluene, and acetic acid | HSDB | ||
| Slight | NIOSH | ||
| Vapor pressure | 1216 mmHg | NIOSH | |
| 1215 mmHg | at 20 °C | CAMEO | |
| 1420 mmHg | at 25 °C | HSDB | |
| Autoignition temperature | Not flammable (USCG, 1999) | CAMEO | |
| Lower explosive limit (LEL) | Nonflammable Gas | NIOSH | |
| Vapor density | 3.4 (air = 1) | HSDB | |
| Critical temperature and pressure | 181.85 °C (359.3 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Source notes
Further notes on Phosgene
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
Phosgene used in anhydrous equipment with reagents is not corrosive to ordinary metals. In presence of moisture, corrosive conditions will develop rapidly, in which case monel, tantalum, or glass lined equipment may be used.
Source: HSDB
Odor
Odor cannot be used as a warning for potential exposure. The odor threshold is reported to be between 0.5 and 1.5 parts per million (ppm) ... and tolerance to the pleasant odor of phosgene occurs rapidly.
Source: HSDB
ONE-HALF PART PER MILLION CAN BE RECOGNIZED THROUGH THE SENSE OF SMELL, BY NORMAL PERSONS ACQUAINTED WITH ITS ODOR, BUT OLFACTORY FATIGUE OR ADAPTATION CAN CAUSE A GRADUALLY INCREASING CONCENTRATION TO GO UNNOTICED.
Source: HSDB
The irritant properties of phosgene are not sufficient to give warning of hazardous concn. A trained observer can recognize 0.5 ppm as being "sweet" & at about 1 ppm, the odor becomes typical of the "musty or newmown-hay" smell usually ascribed to phosgene. Workers exposed to phosgene can lose their ability to detect low concn through olfactory fatigue.
Source: HSDB
05 · Handling and storage
Storing and handling Phosgene
Storage conditions
Phosgene must be stored to avoid contact with water, moisture, or steam since violent reactions occur. Store in tightly closed, steel containers in an isolated area away from the work area and separated form all other materials, as well as sunlight. Although phosgene in anhydrous equipment is not corrosive to ordinary metals, in presence of moisture, use monel, tantalum, or glass-lined storage containers. Phosgene should be stored away from heating and cooling ducts. Containers should be frequently inspected for leaks.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Violent reaction with strong oxidizers, amines, aluminum. Attacks metals in the presence of water. Attacks plastic, rubber, and coatings.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
PHOSGENE is water reactive. Incompatible with strong oxidizing agents, alcohols, amines, alkali. May react violently with aluminum, alkali metals (lithium, potassium, sodium), alcohols (isopropyl alcohol, 2,4-hexadiyn-1,6-diol), sodium azide [Bretherick, 5th ed., 1995, p. 134]. May react vigorously or explosively if mixed with diisopropyl ether or other ethers in the presence of trace amounts of metal salts [J. Haz. Mat., 1981, 4, 291]. Phosgene reacts with phosphate or silicate salts, yielding water-reactive and toxic POCl3 with phosphates (Dunlap, K.L. 2005. Phosgene. In Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc.).
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Phosgene in the storage compatibility matrix →