Substance profile
Oxygen
Oxygen is a colorless gas and is odorless.
01 · Identification
What Oxygen is
Oxygen is a colorless gas and is odorless. It boils at -183 °C, melts at -218 °C.
Under the GHS it carries the signal word Danger.
Other names for Oxygen
- compressed oxygen
- liquid oxygen
- O2
- Lox
- Oxygen, (Liquid)
- Dioxygen
- Molecular Oxygen
- Oxygen Molecule
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 |
|---|---|
| H270 | May cause or intensify fire; oxidiser. |
03 · Physical and chemical properties
Oxygen 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 | -182.96 °C (-297.3 °F) | HSDB | |
| -182.94 °C (-297.3 °F) | at 760 mmHg | CAMEO | |
| -183 °C (-297.4 °F) | ICSC | ||
| Melting point | -218.4 °C (-361.1 °F) | HSDB | |
| -218.33 °C (-361 °F) | CAMEO | ||
| Density | 0.0014 g/cm³ | at 0 °C | HSDB |
| 1.14 g/cm³ | at -183 °C | CAMEO | |
| Solubility | 1 vol gas dissolves in 32 vol water at 20 °C, in 7 vol alcohol at 20 °C; sol in other organic liquids and usually to a greater extent than in water | at 20 °C | HSDB |
| Solubility in water, ml/100ml at 20 °C: 3.1 | at 20 °C | ICSC | |
| Vapor pressure | 7.5006 mmHg | at -211.9 °C | HSDB |
| 38100 mmHg | at -118 °C | ICSC | |
| Lower explosive limit (LEL) | Not flammable in air. | Liquid oxygen | HSDB |
| The substance is a strong oxidant and reacts with combustible and reducing materials, causing fire and explosion hazard. | HSDB | ||
| Vapor density | 1.43 (air = 1) | HSDB | |
| 1.1 (air = 1) | ICSC | ||
| Critical temperature and pressure | -118.95 °C (-182.1 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Fire and explosion
Fire and explosion behaviour of Oxygen
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.
Fire and explosion
Strong oxidizer ... May initiate fire/explosion in combustible materials ... A leak of liquid oxygen onto combustible material represents a severe explosion potential ... /Oxygen, liquid/
Source: HSDB
05 · Handling and storage
Storing and handling Oxygen
Storage conditions
GAS & LIQ: GASEOUS OXYGEN IS STORED ... IN CYLINDERS AT A PRESSURE OF 150-160 ATM, & INSULATED TANKS ARE USED FOR LIQUID OXYGEN; SMALL QUANTITIES OF LIQUID OXYGEN (2-50 L) CAN BE STORED IN DEWAR FLASKS.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Liq: Heat of water will vigorously vaporize liquid oxygen.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
Propellant; ignites upon contact with alcohols, alkali metals, amines, ammonia, beryllium alkyls, boranes, dicyanogen, hydrazines, hydrocarbons, hydrogen, nitroalkanes, powdered metals, silanes, or thiols [Bretherick 1979. p.174]. Heat of water will vigorously vaporize liquid oxygen, pressures may build to dangerous levels if this occurs in a closed container. Liquid oxygen gives a detonable mixture when combined with powdered aluminum [NFPA 491M. 1991].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Oxygen in the storage compatibility matrix →
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