chemi~tryon /tamp/
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edited by:
JAMES 0.SCHRECK Universlw of Nonhern Colorado Greeley. GO 80639
C. MARVINLANG Universitv of Wisconsin Stevens ~ b i n t WI , 54461
A Philatelic History of the Discovery and Isolation of Elements Sylvia Heller and Detlef Heller Ernst-Moritz-Arndt University of Greifswald, Soldtrnannstrasse 16, Greifswald 2200. DDR As illustrated by previous papers in this mini-series ( 1 4 , stamps are interesting and valuable aids in teaching cbemistry because they associate the subject matter taught with a widespread hobby. Moreover, many countries have issued stamps to honor various scientists and to commemorate scientific achievements. One of the many topics covered on stamps, and other philatelic material such as cachets, is the history of the discovery of the elements. Many elements, for example, carbon, sulfur, iron, lead, mercury, copper, silver, and gold, were used in ancient times long before their elementary nature (7) was recognized. However, most of the elements have been discovered and isolated during the last 200 years. Not by chance, this rapid development occurred toward the end of the 18th century for three reasons: (1)the develo~mentof new chemical insights and theorie; (e.g., the overthrow of the phlogiston theorv bv Antoine Lavoisier. the formulation of the atomic theor; dy John Dalton, t h e establishment of the periodic svstem of the elements bv Dmitri I. Mendeleev and Lothar Meyer), (2) the introduction of quantitative work and the develo~mentof analytical chemistry, and (3) the increasing use of instrumental techniques (e.g., the use of spectral analysis and radioactive decay). Oxygen, the most abundant element on earth, was discovered by Joseph Priestley (8, 9) in 1774, even though its elementary nature was not recognized until later by Lavoisier. About the same time, Carl W. Scheele (stamp no. 1) discovered oxygen independently of Priestley. He prepared the so-called "fire air", for example, by heating manganese dioxide with concentrated sulfuric acid (8) as shown by the equation MnO,
+ H,SO,
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MnSO,
+ H,O + XO,
Furthermore. this investigation led Scheele to the discovery and preparation of the "dephlogisticated muriatic acid" (chlorine) and to the discovery and characterization of compounds of manganese and barium. Some of his analyses laid thefuundation for the larerdiscoveryof theelemcnts molybdenum and tungsten (11). The element chromium, given this name because of its brilliantly colored compounds (the Greek word khroma means "color"), was discovered and isolated in an impure form bv Louis Vauouelin (no. 2) in 1797. One vear later he discovered anothernew element, which he idkntified as a constituent of bervl and emerald (8). In 1828 beryllium was isolated by ~ r i e d i i c hWehler, the German chedist known for the demise of the "vital force theory". 12
Journal of Chemical Education
IdentWlcatlon and Descrlptlon of Stamps Issuing
Year of
Stamp No.
Country
lwue
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Germany (GDR) France Italy
1986 1963 1934 1927 1957 1939 1979 1951 1982 1955 1974 1974 1934 1934 1984 1986 1960 1954 1964 1964 1984 1966 1963 1938 1947 1982 1971 1,981 1979 1978 1980 1982
blY
France Sweden Sweden Denmark Germany (FRG) France Germany (GDR) Germany (Berlin) Russia Russia Bulgarla Germany (GDR) Finland Austria Sweden Sweden North Korea
Sweden Sweden France Poland Poland Russia Sweden Germany (FRG) Austria Germany (GDR) France
Scoll Cat. No. 8372 329 190 864 293 1293 329 1379 760 1541 9N345 537 539 2947
370 595 673 674
N/A 711 638 878 401 2519 3888 1389 1300 1093 2089 1838
Further advances in analysis were achieved through the use of electricity by Luigi Galvani (no. 3) and Alessandro Volta (no. 4) (12). For the first time, it became possible to isolate elements in a completely new way. One of the pioneers in the field of electrochemistry was Sir Humphry Davy. During 1807-1808, he succeeded in isolating the elements potassium, sodium, calcium, strontium, magnesium, and barium by means of the electrolysis of a fused salt (8). With the isolation of these metals a number of new, very powerful reductants had become available allowing for the
possibility of isolating further elements. For example, it hecame possible to isolate boron, from boric acid and borax by reduction with potassium, as an olive-green powder. This was first accomplished by Joseph Gay-Lussac and Louis Thenard (no. 5) in 1808 (13). Jon J. Berzelius (nos. 6 and 7) discovered a number of elements. In the summer of 1817 he discovered, in the lead chambers of a sulfuric acid factory, the element selenium, which at first he believed to he the already known element tellurium. In the course of his investigations, however, he found that it was indeed a new element. In 1829 he discovered the element thorium, which he prepared hy the reduction of potassium thorium fluoride, KzThFs, with potassium as shown in the following equation: K,ThF,
+ 4K
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6KF + Th
During 1823-1825 the elements silicon, zirconium, and tantalum were isolated by Berzelius in an impure state. An element found abundantly in the earth's crust is aluminum. In 1754, A1203 was called "alum earth" by Andreas Mareeraf.. hut i t was not until 1825 that Hans Oersted (no. 8) ohtainetl impure aluminum. The first preparation of pure aluminum is credited, however, to Wohler (no. 9), who systematically continued Oersted's experiments with his permission. In 1827 Wohler obtained aluminum by the reaction of anhydrous aluminum chloride with potassium and investigated the chemical behavior of the metal more completely. Aiuminum was prepared for the first time in 1854 by an
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electrolytic method hy Henri St.-Claire Deville (no. 10) in Paris and by Robert Bunsen in Heidelberg (10). The development of spectral analysis by Bunsen and Gustav Kirchhoff (nos. 11and 12) in 1860 (14,15) is a significant event in the history of the discovery of the elements. Although it had been known that compounds of elements cause a characteristic flame coloration, it was only with the development of the spectroscope and the Bunsen burner, which was especially designed for that purpose, that the qualitative analysis of elements from their spectral lines became possible. By the employment of the sp&oscope elements even in quantities of only a few millionths of a milligram could be detected. This brought about essential progreis in analytical chemistry, as well as the purposeful search for new elements. On this basis Bunsen succeeded in discovering the two elements cesium (16) and rubidium (17) in 1860 and 1861, respectively. o n e of
