A colourless odourless gaseous element belonging to group 16 (formerly VIB) of the periodic table; a.n. 8; r.a.m. 15.9994; d. 1.429 g dm−3; m.p. –218.4°C; b.p. –183°C. It is the most abundant element in the earth’s crust (49.2% by weight) and is present in the atmosphere (28% by volume). Atmospheric oxygen is of vital importance for all organisms that carry out aerobic respiration. For industrial purposes it is obtained by fractional distillation of liquid air. It is used in metallurgical processes, in high-temperature flames (e.g. for welding), and in breathing apparatus. The common form is diatomic (dioxygen, O2); there is also a reactive allotrope ozone (O3). Chemically, oxygen reacts with most other elements forming oxides. The element was discovered by Joseph Priestley in 1774.
https://www.webelements.com/oxygen/ Information from the WebElements site