Oxygen is a very important element for life on earth, it is necessary for most life on earth. It is the 8th element on the periodic table.
| Phase | Gas |
| Density | (0C, 101.325 kPa) 1.429 g/L |
| Liquid density at melting point | 1.141 gcm^-3 |
| Melting point | 54.36 K,-218.79 C,-361.82 F |
| Boiling point | 90.20 K,-182.95 C,-297.31 F |
| Critical point | 154.59 K, 5.043 MPa |
| Heat of fusion | (O2) 0.444 kJ mol^-1 |
| Heat of vapoization | (O2) 6.82 kJ mol^-1 |
| Molar heat capacity | (O2) 29.378 J mol^-1 K^-1 |
