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Discovery of oxygen
Who was first prepared him Scheele, a Swedish chemist, in 1772. He identified it as one of the main constituents of air and air called air fire and vitriol. However, who isgenerally regarded as the discoverer is to Priestley, since published his results in 1774, while Scheele delayed its publication until 1777. In its original preparation, Priestley heated what is now knownas mercury oxide, HgO, and observed the evolution of a gas. In this gas called it dephlogisticated air and noted that increased the brightness of a flame. However, it was Lavoisier who recognized thenew gas and an element called oxygen in 1777 (from the Greek oxy acids forming genes).
Unique nature of the oxygen
Several groups of the Periodic Tablethere are marked differences between the first element and others. When oxygen compared with sulfur and other elements of the group, the differences become visible and are caused by:
• The smallsize of oxygen ions.
• The lower electronegativity of the elements O → Po which means less ionic character in its bonds. The O is the second most electronegative element behind the F. This translatesinto a great importance H bond for some compounds with O and negligible for others.
• Oxygen can not extend octet, while sulfur and can accommodate up to 18-in the n = 3. This implies that rates ofsulfur coordination are very varied and high.
Michał Sędziwój of Warsaw, was a Polish alchemist and natural philosopher in the late sixteenth century (c.1592). Sędziwój realized that air is a mixture ofsubstances, one of which (later called oxygen) is a life-giving substance. He correctly equated this "elixir of life" with the gas given off by heating niter (or saltpeter, the mineral form ofpotassium nitrate), driving off the nascent oxygen. This very effective method of extracting oxygen is still demonstrated in elementary chemistry labs every year.
Oxygen was rediscovered by the Swedish...