Walter Noddack

German chemist who, along with Ida Tacke (who later married Noddack), and Otto Berg, reported the discovery of element 43 and element 75 in 1925.

They named element 75 rhenium (Latin Rhenus meaning "Rhine"). Rhenium was the next-to-last naturally occurring element to be discovered and the last element to be discovered having a stable isotope. The existence of a yet undiscovered element at this position in the periodic table had been predicted by Henry Moseley in 1914. In 1925 they reported that they detected the element in platinum ore and in the mineral columbite. They also found rhenium in gadolinite and molybdenite.

Element 43 was named masurium (after Masuria in Eastern Prussia). The group bombarded columbite with a beam of electrons and deduced element 43 was present by examining X-ray diffraction spectrograms. The wavelength of the X-rays produced is related to the atomic number by a formula derived by Henry Moseley. The team claimed to detect a faint X-ray signal at a wavelength produced by element 43. Contemporary experimenters could not replicate the discovery, and in fact it was dismissed as an error for many years. It was not until 1998 that this dismissal began to be questioned. Debate still exists as to whether the 1925 team actually did discover element 43.

Walter Noddack died on 7 December 1960 in Berlin, aged 67.