Discovering Oxygen

The First Reported Discovery of Oxygen was in 1774

Molecular oxygen was first appreciated as a element when it was discovered in 1774 jointly by Joseph Priestley in England (UK) and by Carl Wilhelm Schelle in Sweden. Preistly named this element as "dephlogisticated air" or air that was unable to burn and Schelle termed the element as "fire air". Priestly however, was able to recognise the means by which molecular oxygen is generated when he realised it was produced by green plants (vegetables), and subsequently both Preistly and Schelle discovered the toxicity of pure (1 atm) O₂ to plants. In 1777 Antoine L. Lavoisier in France made the finding that O₂ was a important component of air and was the person who is attributed with naming oxygen. The basis for the name oxygen was the reactivity with other elements that generated oxy-acids and Lavoisier established O₂ was the oxidant of fuels in combustion and it was the oxidant for biological respiration. Unfortunately for Lavoisier, his contributions to science were balanced with a preoccupation involving tax collection, and the culmination of the French Revolution resulted in an unfortunate one way trip to the guillotine for Lavoisier and he had no further dealings with oxygen. The English chemist John Dalton is the person to gave the O symbol to oxygen.

The Discovery of Oxygen Stable Isotopes

The initial concept of isotopes was introduced in 1913 by Soddy (1913) with the need to explain elements that occupy the same position in the periodic table yet have differences in their nuclear properties. The two stable isotopes of oxygen were discovered in the 1920's. Blackett (1925) was the first to encounter an oxygen isotope in a radioactive process, but this observation was not yet attributable to the discovery of a stable isotope. Two years latter Dieke and Babcock (1927) observed a band (A' ) in the solar spectrum near the 7596 Å atmospheric O₂ emission (0-0) A band and Giauque and Johnston (1929a,b) quantitatively ascribed the ¹⁶O¹⁸O species, thereby discovering the ¹⁸O isotope. Shortly thereafter Babcock (1929) found a second A'' in the solar spectrum and Giauque and Johnston (1929c,d) identified this as ¹⁶O¹⁷O and thereby discovered the ¹⁷O isotope. Childs and Mecke (1931) using the atmospheric absorption bands estimated the ¹⁶O : ¹⁷O : ¹⁸O abundance as 630 : 0.2 : 1. With the invention by Aston of the mass spectrometer he was able to refine the relative abundance of oxygen isotopes ¹⁶O : ¹⁷O : ¹⁸O to 536: 0.24: 1. Currently the accepted distribution is 99.7587 : 0.0374 : 0.2039 for ¹⁶O : ¹⁷O : ¹⁸O.

	References
		Aston, F.W. (1932) Nature (London) 130, 21
		Babcock H.D. (1929) Proc. Nat. Acad. Amer. 15, 471
		Blackett, P.M.S. (1925) Proc. R. Soc. (London) Ser. A 107, 349
		Childs, W.H.J. and Mecke, R. (1931) Z. Physik 68, 344
		Dieke G.H. and Babcock H.D. (1927) Proc. Nat. Acad. Amer. 13, 670
		Giauque, W.F. and Johnston, H.L. (1929a) Nature (London) 123, 318
		Giauque, W.F. and Johnston, H.L. (1929b) J. Am. Chem. Soc. 51, 1436
		Giauque, W.F. and Johnston, H.L. (1929c) Nature (London) 123, 831
		Giauque, W.F. and Johnston, H.L. (1929d) J. Am. Chem. Soc. 51, 3528
		Soddy, F. (1913) Chem. News 107, 97

The Discovery of Ozone

The discovery of ozone in 1840 by the German-Swiss chemist Christian Friedrich Schönbein. His method was based on electrical discharge and his discovery came to be the "odor of electricity". In the following two decades ozone was realised to be an allotrope of oxygen and with the O-O-O formula (Rubin 2001). It then took many years (1920's) before the first preparation and isolation of pure liquid ozone. As a general warning and comment; liquid ozone is a hazardous (= explosive) material to work with as many early papers will attest to - play carefully with this if you manufacture some.

	References
		Rubin, M. B. (2001) Bull. Hist. Chem. 26, 40

Discovery The first discovery of Oxygen was by Schelle around 1771, however, he only published this work in 1777 in his only book Chemische Abhandlung von der Luft und dem Feuer (translation: Chemical Treatise on Air and Fire), which was several years after Priestly's first published account.

Practical Experiments A interesting practical site <"Microscale_Gas_Chemistry"> about the discovery of several gases and some interesting experiments for students with Oxygen. See also a more advanced paper on Physical chemistry with liquid oxygen (J. Chem. Ed.).

Molecular Oxygen (O₂)