“We want a heroine or a martyr” when we read about forgotten scientists, says Brigitte van Tiggelen, director of European operations at the Science History Institute. Ida Noddack does not fit that description. Her legacy is complicated by her work for the academic regime established by the Nazi government in Germany in the 1930s, which likely tarnished the postwar judgment of her work. But even before the war, Noddack’s findings were ignored and diminished by his scientific contemporaries. Not only did she discover the element rhenium, one of the last naturally occurring elements to be discovered, but she also suggested that bombardment of heavy nuclei could cause them to decay, four years before the idea of ​​fission was widely accepted. However, she did not celebrate the controversial claims to have discovered the element technetium and the barriers she faced as a woman and largely forgot her story.

Ida Tacke was born in Lackhausen in 1896 as the daughter of a paint and varnish manufacturer. She studied chemical engineering and metallurgy in Berlin and was one of only 20 women in all of Germany who received her doctorate in 1921. The likely plan was for her to return to the family business, suggests van Tiggelen, but Ida clearly had other ideas. She had met Walter Noddack, a former doctoral student of Walther Nernst who now worked in the renowned chemistry department of the Imperial Physical Technical Bureau. In 1923 she began to work in his laboratory as an unpaid “guest researcher” and joined his search for the missing elements under manganese in the periodic table (atomic numbers 43 and 75). In 1926 they were married.

Although she clearly did not have Walter’s status, van Tiggelen said Ida herself made it clear that they were employees and developed the analytical process that would be required to isolate the elements together. They began looking for minerals that contained manganese and then platinum and examined about 1,800 ores, including meteorites. Finally, in 1925, they announced with Otto Berg from the lamp factory Siemens & Halske, who carried out X-ray spectroscopy, that they had identified both rhenium (75) and element 43. The chairwoman stated that she was the first “colleague” to contact turned the club.

Item 43 became a stain on their reputation

The Noddacks had only isolated 1 g of rhenium by 1929, but later larger amounts were found in ore molybdenite, so that 120 kg could be produced each year by the mid-1930s. They received patents for various applications, including lamp filaments and catalysts, and were nominated for several Nobel Prizes without ever winning.

The situation was different for the second element, which they supposedly discovered but couldn’t isolate. “Element 43 has damaged their reputation,” says van Tiggelen. Their discovery was controversial, but they refused to withdraw, labeling the element by the name they gave it – Masurium. “They were accused of being completely inflexible and of not withdrawing their claim, even if they were more or less shown that it could not be element 43,” says the chemist and writer Eric Scerri of the University of California at Los Angeles US.

Although they tried to isolate the element until the 1950s, they couldn’t because it decays radioactively and is only naturally present in tiny traces (from the more recent uranium decay). ‘Never in hers [wildest] They imagined dreams that it would be a disappearing element, ”says van Tiggelen. Ultimately, Element 43 was artificially created by Emilio Segrè and Carlo Perrier in 1937 by bombarding a molybdenum plate with a deuteron beam, and in the 1950s it was officially called technetium.

In 1988 Belgian physicist Pieter van Assche and US colleagues re-analyzed the Noddacks’ X-ray data and argued that they had discovered technetium. He noted that they claimed they only observed it in uranium-bearing ores, a correlation that would have been unknown in 1925 and that van Assche calls the “credibility test”. However, the majority still believe that even if there had been traces it would not have been possible to detect the element above the background x-ray signal. “It would have required your instrument to be much more efficient than you claimed,” says Van Tiggelen.

Ironically, although her failure to discover element 43 was due to a lack of understanding of nuclear chemistry, it was Ida’s observations about the possibility of nuclear fission that, in some ways, showed her to be ahead of others in her thinking. In 1934, Enrico Fermi proposed to have discovered elements 93 and 94 (neptunium and plutonium) that had formed from nuclear fusion when uranium was bombarded with neutrons. But Ida, with her expertise in element hunting, criticized Fermi’s conclusions in an article she published without Walter (who perhaps found this too controversial).

In her work, she said that Fermi “did not compare his new radio element with all known elements”. He had stopped on the leash, which was the established endpoint of radioactive decay. Ida also said that its products did not perform as expected based on their positions on the periodic table. Instead, she suggested, “When heavy nuclei are bombarded by neutrons, it is reasonable to assume that they will break down into numerous large fragments that are isotopes of known elements but not neighbors of the bombarded elements.”This was five years before the split was confirmed by physicists Lise Meitner and Otto Frisch, but as van Tiggelen admits, “She is certainly not the one who discovered it because she had no theory [or have] experimental evidence … but she was the first to suggest it. ‘

It was bitter that no famous chemist or physicist would listen to it

Unfortunately, their ideas have been mocked by the rest of the predominantly male scientific community. Their suggestion was rejected by leading German scientist Otto Hahn, who repeated Fermi’s results between 1935 and 1938 and finally found that he had formed barium from bombardment with uranium. ‘[But] for these four years [they] I tried all kinds of crazy accommodations for the things that they actually saw, ”says van Tiggelen. When Walter brought up her rejection of Ida’s idea, Hahn reportedly told him that he wanted to ignore her because he didn’t want to embarrass his wife.

Van Tiggelen says her gender wasn’t the only reason her ideas were immediately rejected. ‘[The Noddacks] were no longer viewed well because of them [contested] Masurium claim. ‘It wasn’t until decades later that Hahn admitted she was right, having previously refused to give her credit. Until her death, “she was bitter that no famous chemist or physicist had listened to her,” says metallurgist Fathi Habashi of Laval University in Quebec, Canada. Habashi met and corresponded with Noddack after meeting her at a conference in Germany in the 1950s. He remembers one visit when she showed him a rhenium ashtray given to her by the mining company that extracted the metal.

The other factor from the 1930s onwards was the rise of Nazism in Germany and the engagement of the Noddacks. “They weren’t members of the NSDAP, but they were definitely supporters of this type of ideology,” says van Tiggelen. In 1935, after the departure of the Jewish chemist Georg Hevesy, Walter was promoted to a professorship at the University of Freiburg, and in 1941 the couple moved to the University of Strasbourg, which was then under German control. “Apparently Hitler viewed the University of Strasbourg as the jewel in the crown,” says Scerri. ‘[The Noddacks] were celebrated as a great German couple doing something similar to Marie and Pierre Currie, ”adds van Tiggelen. Ironically, given the Nazis’ regressive ideology regarding women’s roles, this was the only time Ida had a paid university professorship.

After the war, Germany went through the process of denazification and only the exonerated academics could keep their jobs. Ida and Walter were officially exonerated, but they were depraved and couldn’t find a job at any major university. Eventually Walter founded an institute for geochemistry in Bamber and Ida returned to her role as an unpaid assistant. In this atmosphere, criticism continued for their claiming to have discovered element 43, and Segrè even accused them of being dishonest about it.

Historian Gildo Magalhăes Santos of the University of Săo Paulo, Brazil, recently reassessed Noddack’s work, believing that her scientific ideas were far more pervasive than generally accepted. For example, in the one book she wrote for a popular audience, she wrote that science is a continuous revelation of the truth. “That wasn’t common in the 1930s or 40s when she wrote the book,” says Santos. With her understanding of the distribution of elements, she also suggested that marine animals would use traces of heavy metals that could be found in seawater – before the discovery of the cobalt-containing vitamin B12.

It could be extremely conservative even if it expresses other revolutionary ideas

One of the bold ideas she put forward was the hypothesis that the creation and distribution of elements in the universe was not random but was related to nuclear properties. “She called it the universal distribution of elements … and that idea was very important,” explains Santos. It led them to the hypothesis that the nucleus of an atom is structured analogously to the electronic structure itself and that particles exist in different shells with increasing atomic numbers. Eventually, this highly speculative idea gained ground with a Nobel Prize in Physics for core-shell theory in 1963. “It turned out perfectly right,” says Scerri. ‘It was almost a different prediction [of hers] that came true. ‘

Not all of their ideas were useful, however. She believed that matter should be organized on isotopes rather than the newer concept of atomic number. “It had an extended periodic table in which the isotopes were the basic elements and not the elements in themselves,” explains Santos. She thought classification based on core structure might provide a more “natural” system. Chemists ultimately didn’t find this idea useful, and Scerri suggests that this is an example of how it could be extremely conservative, even as it expresses other revolutionary and speculative ideas. “That is often the case with great scientists,” he adds.

While Ida Noddack may once have been seen as the German Marie Curie, she is not remembered in the same way. In contrast to Curie, “she lacked a” fan club “,” says Santos. However, van Tiggelen warns that it is difficult to assess the work of former female scientists. “There are a lot of pitfalls, and one of them, of course, is overcrediting.” What she has achieved is always complicated by the time she lived in, both in terms of how she was treated as a scientist and in terms of her own role in the Nazi academic machine. For Santos, she is a scientist to be remembered for her bold thinking. “She wasn’t afraid to hypothesize, even if it wasn’t easy to prove.”

Rachel Brazil is a science writer based in London, United Kingdom

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