Ogawa's Discovery of Nipponium and Its Re-evaluation
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概要
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I shall begin this article with discovery of elements which is the basement of general chemistry, and shift to discovery of rare gases by Sir William Ramsay (1852-1916), and then move to the case of the Japanese chemist Masataka Ogawa (1865-1930) who worked on the discovery of nipponium, the element once accepted in the periodic table, then neglected, and now ascribed to rhenium. History of the chemical elements may be back to the ages of Greek philosophers. Empedocles (483-43 5BC) first proposed the concept of four elements, which was succeeded and authorized by Aristotle (384-322BC) later. However, the modern concept of the chemical element was set up on the basis of scientific rationalism after the 18th Century. The number of the elements discovered scientifically is beyond one hundred. Now the atomic number of the element attained to 118 including man-made ones. The history of discovery of elements appears to be full of intellectual endeavour of mankind. When inspecting its details there were peaks and bottoms of discovered number of the elements for one quarter of a century (Fig. 1). The maximum activity was seen in the last quarter of the 19th Century when Ramsay and Marie Curie (1867-1934) were working as productive scientists. Most of naturally existing elements were found by the end of this period. Then discovery of radioactive and man-made elements became a main stream. Therefore search aiming at remaining natural elements in the first quater of the 20th Century was a very difficult work. Masataka Ogawa's activity was just overlapping this period. The last stable element existing in nature, rhenium, was found in 1925. As will be described later. Ogawa actually separated and identified this element already in 1908.
- 日本科学史学会の論文
- 2000-03-30