The cosmic abundance-the estimated total abundance in the universe-is between three and seven atoms per atom of silicon, which is taken as the standard. The natural abundance of nitrogen in Earth’s crust is 0.3 part per 1,000. Nitrogen constitutes on the average about 16 percent by weight of the complex organic compounds known as proteins, present in all living organisms. In combination, nitrogen is found in the rain and soil as ammonia and ammonium salts and in seawater as ammonium (NH 4 +), nitrite (NO 2 −), and nitrate (NO 3 −) ions. Another material rich in nitrogen is guano, found in bat caves and in dry places frequented by birds. Nitrogen also occurs in mineral deposits of nitre or saltpetre (potassium nitrate, KNO 3) and Chile saltpetre (sodium nitrate, NaNO 3), but these deposits exist in quantities that are wholly inadequate for human needs. Free nitrogen is found in many meteorites in gases of volcanoes, mines, and some mineral springs in the Sun and in some stars and nebulae. The atmosphere also contains varying small amounts of ammonia and ammonium salts, as well as nitrogen oxides and nitric acid (the latter substances being formed in electrical storms and in the internal combustion engine). The atmosphere of Earth consists of 75.51 percent by weight (or 78.09 percent by volume) of nitrogen this is the principal source of nitrogen for commerce and industry. Occurrence and distributionĪmong the elements, nitrogen ranks sixth in cosmic abundance. The inability of nitrogen to support life (Greek: zoe) led Lavoisier to name it azote, still the French equivalent of nitrogen. Nitrogen first was considered a chemical element by Antoine-Laurent Lavoisier, whose explanation of the role of oxygen in combustion eventually overthrew the phlogiston theory, an erroneous view of combustion that became popular in the early 18th century. Later work showed the new gas to be a constituent of nitre, a common name for potassium nitrate (KNO 3), and, accordingly, it was named nitrogen by the French chemist Jean-Antoine-Claude Chaptal in 1790. At about the same time, nitrogen also was recognized by a Scottish botanist, Daniel Rutherford (who was the first to publish his findings), by the British chemist Henry Cavendish, and by the British clergyman and scientist Joseph Priestley, who, with Scheele, is given credit for the discovery of oxygen. The “fire air” was, of course, oxygen and the “foul air” nitrogen. Carl Wilhelm Scheele, a Swedish chemist, showed in 1772 that air is a mixture of two gases, one of which he called “fire air,” because it supported combustion, and the other “foul air,” because it was left after the “fire air” had been used up.
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