Oxygen Formula

 

Oxygen Formula 

Many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as well as major components of the inorganic compounds of animal shells, teeth, and bones. Most of the matter of living organisms is oxygen as a component of water, the main component of life forms. Oxygen is continuously replenished in the Earth's atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too chemically reactive to remain a free element in the air without being continuously replenished by the photosynthetic action of living organisms. Another form (allotrope) of oxygen, ozone (O

3), strongly absorbs ultraviolet UVB radiation, and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a by-product of smog and therefore a pollutant.

Oxygen was isolated by Michael Sendivogius before 1604, but it is generally believed that the element was discovered independently by Carl Wilhelm Scheele in Uppsala in or before 1773 and by Joseph Priestley in Wiltshire in 1774. The work was published first. However, Priestley called oxygen "dephlogisticated air" and did not recognize it as a chemical element. The name oxygen was introduced in 1777 by Antoine Lavoisier, who was the first to recognize oxygen as a chemical element and correctly characterize the role it plays in combustion.

Common uses of oxygen include the manufacture of steel, plastics, and textiles, brazing, welding and cutting of steel and other metals, rocket propulsion, oxygen therapy, and life support systems in aircraft, submarines, spaceflight, and diving.