Oxygen (Oxygenium,) is a chemical element of group VI periodic system of elements of D. I. Mendeleyev. Serial number 8, atomic weight of 16. Colorless gas without smell and taste, consisting of diatomic molecules O2. Oxygen is the most abundant element in the earth's crust. Free oxygen is almost exclusively in the atmosphere, dissolved in the waters of the rivers, seas, oceans. Oxygen comes from the water, most of minerals, organic matter, is indispensable components of organisms.
In the body of oxygen forms hemoglobin (see) unstable connection, the emergence and collapse which underlies the process of respiration (see). Prolonged inhalation of pure oxygen causes inflammation of the mucous membranes of the respiratory tract.
In medicine oxygen is used (in the form of breathing mixtures) with some lung and heart diseases and for artificial respiration during hypoxia (oxygen starvation), carbon monoxide poisoning and other Alotropicas modification (a form element) oxygen - ozone - O3 has a strong characteristic odor and is a strong oxidant. About the use of oxygen for medical purposes, see Oxygen therapy.