Most of this amount is oxygen found in silicates. Oxygen is absolutely vital for sustaining life on earth. The United States annually produces 15-million tons of liquid oxygen for applications in industry, aerospace, the military and medicine. It is normally supplied under pressure in steel cylinders or as liquid oxygen in insulated containers.
Oxygen reacts with virtually every element to produce oxides.
The ten most common compounds in the earth's crust are all oxides. Most of the lanthanides exist in nature as their oxides. Even the noble gases are not totally immune to forming oxides. There are two allotropes of oxygen. The latter is known as ozone .