Noddack, Walter

Noddack, Walter (1893-1960) German chemist who, working with his wife, Ida Tacke, discovered the elements rhenium and technetium, and did research on the photopigments of the eye. 

Rhenium (75) was discovered in 1925 by Ida Tacke and Walter Noddack as the last naturally occurring element. The first artificially produced element was identified by Emilio G. Segre in 1937. Ernest Lawrence detected technetium in a molybdenum sample, which he had bombarded in his cyclotron. All elements discovered since then have been generated artificially. 

Rhenium - the atomic number is 75 and the chemical symbol is Re. The name derives from the Latin rhenus for the Rhine river in Germany . It was discovered by x-ray spectroscopy in 1925 by the German chemists, Walter Noddack, Ida Tacke and Otto Berg. 

Rhenium Re 1925 (Berlin, Germany) Walter Noddack, Ida Tacke Noddack and Otto Berg (all German) 155... 

Technetium Tc 1925 (Berlin, Germany) 1937 (Berkeley, California) Walter Noddack and Ida Tacke Noddack (both German) Emilio Segre (Italian-American) and Carlo Perrier (Italian) 130... 

The element was discovered in 1925 by Walter Noddack, Ida Tacke Noddack, and 0. Berg. They detected it by x-ray examination of platinum ores. X-ray studies also showed its occurrence in columbite and other minerals. It was named after the German river Rhine, called Rhenus in Latin. In 1929, Walter and Ida Noddack produced Ig of rhenium metal from 660 kg of Norwegian molybdenite. 

Two new elements of the manganese group, numbers 43 (eka-manganese) and 75 (dwi-manganese), were announced in June, 1925, by the German chemists Dr. Walter Noddack and Dr. Ida Tacke of the Physico-Technical Testing Office in Berlin and Dr. Otto Berg of the Werner-Siemens Laboratory. The discovery was not accidental, but the... 

In May 1925, at last, the X-ray measurements seemed to indicate the presence of both elements 43 and 75. The first mention of the discovery was made at a very high level, at a meeting of the Preujiische Akademie der Wissenschaften, thanks to Walther Nernst who had been Walter Noddack s mentor. [17] The results were published in the prestigious journal Die Naturwissenschaften soon after, in a two-fold contribution. A first section of the paper is devoted to the analytical and geochemical part of the investigation, whereas the second section deals exclusively with the X-ray spectroscopy, [18] and Ida co-authors both contributions. In Walter s and Ida s mind however, the quest was not yet finished. Walter Noddack publicly declared that the crucial point to assess the existence of these two new elements was to produce samples and to hand them over to colleagues. [19]... 

Walter and Ida (just married) were very much aware of the fact that the only possibility to establish their credibility was to produce weighable samples of both rhenium and masurium, and decided to explore new ways of enrichment and production. One obvious way was to find ores that contained more rhenium and masurium than those already used. To achieve this, the couple undertook several trips to Scandinavia and Russia in 1926-1930. [20] The Noddacks convinced Siemens und Halske that rhenium could become an industrial product very soon thanks to Siemens sponsoring (40000 Marks) and material help (a small laboratory was set up at their disposal for several months), the first gram of a rhenium salt was obtained in 1929. [21] At this point, the investigation of the chemical properties of rhenium could begin and they showed that most of the predictions made on the basis of the spectra alone were not far from reality. 

On several occasions, letters were sent to the couple asking whether the discovery had received confirmation or not. [51] Walter Noddack just kept silent, and even more and more silent as the years went by. The Noddacks felt they were unable to provide any kind of proof. Not only were they unable to show a sample of masurium which would have, as had been the case for rhenium, closed the controversy on the existence of the element, but even the original photographic plate of typical spectral lines was never shown as a piece of evidence. [52]... 

Until the end of their lives, Ida and Walter Noddack kept an eye on the chemistry of rhenium and especially on that of technetium. This is especially remarkable when... 

Walter Noddack (1893-1960) began studying chemistry, physics and mathematics at the University of Berlin in 1912. Having volunteered during World War I, he received his doctorate in 1920 only, under the direction of Nernst on Einstein s law of photochemical equivalence. He became di-... 

Draft of a letter of 6. September 1936 to Walter s nephew, K. U. Leuven Archives, Noddack-Tacke Papers, 1187. This has to be interpreted carefully, because on several occasions her memory is biased and the story reconstructed. 

Auer von Welsbach was another chemist who doubted the validity of fhe American results. Finally, the married couple, Ida Noddack (nee Tacke, 1896-1978) and Walter Noddack (1893-1960), embarked upon a quest for fhe element 61. Husband and wife were greatly stimulated by their recent discoveries of masurium and rhenium. The Noddacks, in collaboration with Berg, began their investigations with an enormous amount of rare-earfh minerals (Noddack ef al., 1925). They firsf of all produced a number of very pure samples of neodymium and samarium. They made use of the most sensitive and accurate methods of analysis of fhat time, allowing to detect element 61 if if were 10 million times more rare than neodymium and samarium. However, their work remained without success. 

Rhenium. The element rhenium, atomic number 75, was fliscovered by the Gennan chemists Walter Noddack and Ida Tacke in 1925. The principal compound of rhenium is potassium perrhenate, KReO. a colorless substance. In other compounds all oxidation numbers from -f-7 to —1 are represented examples are RCgOj, ReOg, ReClg, Re02, Re20g, Re(OH)2. 

Rhenium was discovered by a German research team that included Walter Noddack (1893-1960), IdaTacke (1896-1979), and Otto Berg. These scientists knew that there were several empty boxes in the periodic table that represented elements that had not yet been discovered. The periodic table is a chart that shows how chemical elements are related to one another. In 1925, the German team announced that they had found two elements. They were correct about one (element number 75) but wrong about the other (element number 43). 

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