Walter Noddack (17 August 1893 – 7 December 1960) was a German chemist. He, Ida Tacke (who later married Noddack), and Otto Berg reported the discovery of element 43 and element 75 in 1925.

Rhenium

They named element 75 rhenium (

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''Rhenus'' meaning "

Rhine The Rhine ( ) is one of the List of rivers of Europe, major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Austria–Swit ...

").

Rhenium Rhenium is a chemical element; it has symbol Re and atomic number 75. It is a silvery-gray, heavy, third-row transition metal in group 7 of the periodic table. With an estimated average concentration of 1 part per billion (ppb), rhenium is one ...

was the last element to be discovered having a stable isotope. The existence of a yet undiscovered element at this position in the

periodic table The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods") and columns (" groups"). It is an icon of chemistry and is widely used in physics and other s ...

had been predicted by

Henry Moseley Henry Gwyn Jeffreys Moseley (; 23 November 1887 – 10 August 1915) was an English physicist, whose contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic numb ...

in 1914. In 1925 they reported that they detected the element in platinum ore and in the mineral

columbite Columbite, also called niobite, niobite-tantalite and columbate, with a general chemical formula of , is a black mineral group that is an ore of niobium. It has a submetallic luster, a high density, and is a niobate of iron and manganese. Niobite ...

. They also found rhenium in

gadolinite Gadolinite, sometimes known as ytterbite, is a silicate mineral consisting principally of the silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron with the formula . It is called gadolinite-(Ce) or gadolinite-(Y), depending o ...

and

molybdenite Molybdenite is a mineral of molybdenum disulfide, Mo S2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum at ...

. In 1928 they were able to extract 1 g of the element by processing 660 kg of molybdenite. These achievements led to Walter and Ida being awarded the

German Chemical Society The German Chemical Society () is a learned society and professional association founded in 1949 to represent the interests of German chemists in local, national and international contexts. GDCh "brings together people working in chemistry and th ...

's prestigious

Liebig Medal The Liebig Medal (German: ''Liebig-Denkmünze'') was established by the Society of German Chemists () in 1903 to celebrate the centenary of Justus von Liebig. Since 1946 it has been awarded by the Society of German Chemists (''Gesellschaft Deutsc ...

in 1931.

Technetium

Element 43 was named masurium (after

Masuria Masuria ( ; ; ) is an ethnographic and geographic region in northern and northeastern Poland, known for its 2,000 lakes. Masuria occupies much of the Masurian Lake District. Administratively, it is part of the Warmian–Masurian Voivodeship (ad ...

in Eastern Prussia). The group bombarded

with a beam of

electron The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up qua ...

s and deduced element 43 was present by examining

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

diffraction

spectrogram A spectrogram is a visual representation of the spectrum of frequencies of a signal as it varies with time. When applied to an audio signal, spectrograms are sometimes called sonographs, voiceprints, or voicegrams. When the data are represen ...

s. The

wavelength In physics and mathematics, wavelength or spatial period of a wave or periodic function is the distance over which the wave's shape repeats. In other words, it is the distance between consecutive corresponding points of the same ''phase (waves ...

of the X-rays produced is related to the atomic number by a formula derived by

. 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. John T. Armstrong of the

National Institute of Standards and Technology The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into Outline of p ...

ran computer simulations of the experiments and obtained results very close to those reported by the 1925 team; the claim was further supported by work published by David Curtis of the

Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development Laboratory, laboratories of the United States Department of Energy National Laboratories, United States Department of Energy ...

measuring the (tiny) natural occurrence of technetium. Debate still exists as to whether the 1925 team actually did discover element 43.

Academic career

Noddack was born in

Berlin Berlin ( ; ) is the Capital of Germany, capital and largest city of Germany, by both area and List of cities in Germany by population, population. With 3.7 million inhabitants, it has the List of cities in the European Union by population withi ...

. He became professor for physical chemistry at the

University of Freiburg The University of Freiburg (colloquially ), officially the Albert Ludwig University of Freiburg (), is a public university, public research university located in Freiburg im Breisgau, Baden-Württemberg, Germany. The university was founded in 1 ...

in 1935 and in 1941 at the

Reichsuniversität Straßburg The Reichsuniversität Straßburg was founded in 1941 by the Nazis in Alsace after the annexation of Alsace-Lorraine by Nazi Germany. The University of Strasbourg had moved to Clermont-Ferrand in 1939. The university's purpose was to restore ...

. After

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

he changed to the

University of Bamberg The University of Bamberg () in Bamberg, Germany, specializes in the humanities, cultural studies, social sciences, economics, and applied computer science. Campus The university is partly housed in historical buildings in Bamberg's Old Town. ...

and in 1956 he became director of the newly founded Research Institute for

geochemistry Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...

there. He died in Berlin.

References

* {{DEFAULTSORT:Noddack, Walter 1893 births 1960 deaths German physical chemists Discoverers of chemical elements Scientists from Berlin Technische Universität Berlin alumni Academic staff of the University of Freiburg Academic staff of the University of Bamberg