| Name | Symbol | Density (g L-1 at STP*) | Boiling Point (K at 1 atm) |
|---|---|---|---|
| Air | 1.29 | ||
| Ammonia | NH3 | 0.771 | 240 |
| Carbon dioxide | CO2 | 1.98 | 195 |
| Carbon monoxide | CO | 1.25 | 82 |
| Chlorine | Cl2 | 3.21 | 238 |
| Hydrogen | H2 | 0.0899 | 20 |
| Hydrogen chloride | HCl | 1.64 | 188 |
| Hydrogen sulfide | H2S | 1.54 | 212 |
| Methane | CH4 | 0.716 | 109 |
| Nitrogen | N2 | 1.25 | 77 |
| Nitrogen (II) oxide | NO | 1.34 | 121 |
| Oxygen | O2 | 1.43 | 90 |
| Sulfur dioxide | SO2 | 2.92 | 263 |
| * STP is defined as 273 K and 1 atm | |||