6964. Oxygen

Nomenclature

CAS number: 7782-44-7

Description and references

O; at. wt 15.9994; at. no. 8; valence 2. Group VIA (16). Occurs normally as the diatomic gas O2, also as ozone O3. Atomic oxygen (O) can be prepd. Three naturally occurring isotopes: 16 (99.759%); 17 (0.037%); 18 (0.204%); artificial radioactive isotopes: 13-15; 19; 20. The most abundant element on earth; makes up 46.6% of earth's crust; 20.95% by vol of dry air. Obtained on a large scale by liquefaction of air. First obtained by Scheele in 1771 and independently by Priestley in 1774. Monograph: M. Ardon, Oxygen: Elementary Forms and Hydrogen Peroxide (Benjamin, New York, 1965) 106 pp. Review of oxygen and its compounds: Ebsworth et al., in Comprehensive Inorganic Chemistry vol. 2, J. C. Bailar, Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 685-794; A. H. Taylor in Kirk-Othmer Encyclopedia of Chemical Technology vol. 16 (Wiley-Interscience, New York, 3rd ed., 1981) pp 653-673.

Properties

Colorless, odorless, tasteless, neutral gas; non-flammable, supports combustion. Oxidizer. d0 (gas) 1.429 g/l; d-183 (liquid) 1.14 g/ml. mp -218.4°. bp -182.96°. Critical temp -118.95°. Critical press. 50.14 atm. Heat of vaporization (-183°): 50.9 cal/g. Usually marketed under pressure in metal cylinders. One vol gas dissolves in 32 vols water at 20°; in 7 vols alcohol at 20°; also sol in other organic liquids and usually to a greater extent than in water. Caution: Avoid smoking, flames, electric sparks; explosion hazard.

Use

In oxyhydrogen or oxyacetylene flame for welding metals and for lighting (calcium light, etc); submarine work by divers, propellant for rockets. In the production of synthesis gas which can be used in the Fischer-Tropsch process for liquid fuels.

Therapeutic Category

Medicinal gas to relieve hypoxia; at hyperbaric pressures in cardiac and other surgery, anaerobic infections, carbon monoxide poisoning; in cryotherapy (liq form).

Therapeutic Category (Veterinary)

In hypoxia and in conjunction with volatile anesthetics.