O; at. wt. 15.9994; at. no. 8; valence 2. 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 priestly in 1774. Monograph: M. Ardon, Oxygen - Elementary Forms and Hydrogen Peroxide (Benjamin, New York, 1965) 106 pp. Review of oxygen and its compounds: Ebsworthet 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.

Colorless, odorless, tasteless, neutral gas; supports combustion. 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.

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 Fisher-Tropsch process for liquid fuels. Caution: Avoid smoking, flames, electric sparks - explosion hazard.

THERAP CAT: Medicinal gaz to relieve hypoxia; at hyperbaric pressure in cardiac and other surgery, anaerobic infections, carbon monoxide poisoning; in cryotherapy (liq form).

THERAP CAT (VET): In hypoxia and in conjuction with volatile anesthetics.
Ref.: 6917, 1101 pp.
The Merck Index - Eleventh Edition.
Copyright 1989 by Merck & Co., Inc.