It can also be obtained by heating certain of its compounds, such as barium peroxide, potassium chlorate, and the red oxide of mercury. 5 Uses Oxygen is of great importance in the chemical and the iron and steel industries. Its major use is in steel production, for example in the Bessemer process . The oxyacetylene torch is another important industrial application. Oxygen is utilized in medicine in the treatment of respiratory diseases and is mixed with other gases for respiration in submarines, high-flying aircraft, and spacecraft.
Liquid oxygen is used as an oxidizer in the fuel systems of large rockets.
6 Oxygen was formerly the official standard for the atomic weights of elements. The chemists used natural oxygen, a mixture of three isotopes, to which the value of 16 was assigned while the physicists assigned the value of 16 specifically to the oxygen isotope 16. In 1961 carbon-12 replaced oxygen as the standard. The Columbia Encyclopedia, Sixth Edition.