Definition of Oxygen

Oxygen: A colorless, odorless and tasteless gas that makes up about 20% of the air we breathe (and at least half the weight of the entire solid crust of the earth) and which combines with most of the other elements to form oxides. Oxygen is essential to human, animal and plant life.

The chemical symbol for the element oxygen is O. As a medicinal gas, oxygen contains not less than 99.0% by volume of O₂.

Oxygen was discovered by Scheele and Priestly independently of each other in 1772 and 1774, respectively. They did not name it "oxygen." Priestly called it dephlogisticated air. (Priestly discovered three other chemical compounds, one of which, nitrous oxide - "laughing gas" - is still used today as a mild anesthetic agent, as during dental procedures.)

The word "oxygen" came from the French "oxygene." It was so named by the French scientist Antoine Lavoisier (1743-94) who thought it was a necessary ingredient in all acids. This is not so. Hydrochloric acid (HCl), for example, contains no oxygen.

Shortly after its discovery, oxygen was used for medical purposes. In 1780 Chaussier in France experimented with giving oxygen to newborn infants who had failed to establish normal breathing. Much later, in 1928, Flagg described a procedure for intubation and intermittent positive pressure insufflation ("bagging") with a mixture of oxygen and carbon dioxide for resuscitation of newborns.