Dobereiner, Wolfgang

Johann Wolfgang Dobereiner, 1780-1849, Professor of chemistry at Jena. His discovery of the triads was an important step toward the systematic classification of the chemical elements He wrote many books and papers on general and pharmaceutical chemistry, mineral waters, the manufacture of vinegar, and the use of platinum as a catalyst, The original of this portrait is in the City Museum at Jena. 

Schiff, J., Bnefwechsel zwiscben Goethe und Johann Wolfgang Dobereiner... 

Prandtl, W., Johann Wolfgang Dobereiner, Goethe s chemical adviser, J. 

Ever since Lavoisier had published his list of thirty-three elements in 1789, chemists had been seeking for ways to order and classify them. Lavoisier divided the elements into gases, non-metals, metals, and earths (which included the compounds lime and magnesia). In 1829, by which time the list had expanded somewhat, Johann Wolfgang Dobereiner in Germany noticed that many elements could be grouped into threes ( triads ) whose members... 

The first man to discover a promising relationship among several elements was the German chemist Johann Wolfgang Dobereiner. In 1829, he ran into the idea of triads. 

Dobereiner s triads /doh-ber-y-nerz/ Triads of chemically similar elements in which the central member, when placed in order of increasing relative atomic mass, has a relative atomic mass approximately equal to the average of the outer two. Other chemical and physical properties of the central member also lie between those of the first and last members of the triad. The German chemist Johann Wolfgang... 

The first to catch a glimmering of order was the German chemist Johann Wolfgang Dobereiner (1780-1849). In 1829, he noted that the element bromine, discovered three years earlier by the French chemist Antoine Jerome Balard (1802-76), seemed just halfway in its properties between chlorine and iodine. (Iodine had been discovered by... 

Delville, Edotrard ( - ), 27 Depuydt, Juhen (1842-1919), 28,29 Deville, Henri Sainte-Claire (1818-1881), 94,104,106 Dijken, Bonno van (1866-1900), 200 Dobereiner, Joharm Wolfgang (1780-1849), 240... 

Interestingly, as a so-called Dobereiner triad (i.e., a triad of elements, whose chemical similarities were recognized by German chemist Johann Wolfgang Dobereiner in the nineteenth century), sulfur, selenium and tellurium played a role in the initial construction of the periodic table. 

Experiments inspired by Prout s hypothesis provided an increasingly accurate set of atomic weights, which could then be used to try to order the elements in the periodic system. Many of the pioneers of the periodic system, including Wolfgang Dobereiner, Leopold Gmelin, Max Pettenkofer,Jean Baptiste Andre Dumas,... 

Lavoisier develop the calorimeter. German chemist Johann Wolfgang Dobereiner discovers that platinum can act as a catalyst. Swedish chemist Carl Wilhelm Scheele discovers lactic acid. 

Hydrogen was first well identified by Cavendish in 1766. Its burning to water and the parallel and more difficult decomposition of water to H2 and O2 were cornerstones of Lavoisier s chemical revolution. The reaction was just as reluctant to go in the 1780s as it is today. There were no safety matches until 1855. So Lavoisier set it off with an electric spark. And within 50 years, a German chemist, Johann Wolfgang Dobereiner, used the same H2 and O2 reaction, now catalyzed, as a ready source of fire, replacing other sources of fire in home and laboratory. 

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