Otto Berg (scientist)
Encyclopedia
Otto Berg was a German scientist. He is one of the scientists credited with discovering rhenium
, the next-to-last naturally occurring element to be discovered and the last element to be discovered having a stable isotope.
, Ida Tacke, and Otto Berg reported that they detected the element in platinum ore and in the mineral columbite
. They also found rhenium in gadolinite
and molybdenite
.
In 1928 they were able to extract 1 gram of the element by processing 660 kg of molybdenite.
. They reported the discovery of element 75 and element 43 in 1925 and named element 43 masurium (after Masuria
in eastern Prussia
, now in Poland
, the region where Walter Noddack's family originated). The group bombarded columbite with a beam of electron
s and deduced element 43 was present by examining X-ray
diffraction spectrogram
s. The wavelength
of the X-rays produced is related to the atomic number by a formula derived by Henry Moseley
in 1913. 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 it was dismissed as an error for many years.
In 1998, John T. Armstrong of the National Institute of Standards and Technology
performed computer simulations of the 1925 experiments and obtained results quite similar to those reported by the Noddack team. He claimed that this was further supported by work published by David Curtis of the Los Alamos National Laboratory
measuring the (tiny) natural occurrence of technetium. Noddack's experimental results have never been reproduced, and they were unable to isolate any element 43. Debate still exists as to whether the 1925 team discovered element 43.
Discovery of element 43 was finally confirmed by a 1937 experiment in Sicily.
Rhenium
Rhenium is a chemical element with the symbol Re and atomic number 75. It is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. With an average concentration of 1 part per billion , rhenium is one of the rarest elements in the Earth's crust. The free element has...
, the next-to-last naturally occurring element to be discovered and the last element to be discovered having a stable isotope.
Rhenium
In 1925 in Germany, Walter NoddackWalter Noddack
Walter Noddack was a German chemist. He, Ida Tacke , and Otto Berg reported the discovery of element 43 and element 75 in 1925.-Rhenium:...
, Ida Tacke, and Otto Berg reported that they detected the element in platinum ore and in the mineral columbite
Columbite
Columbite, also called niobite, niobite-tantalite and columbate [2O6], is a black mineral group that is an ore of niobium and tantalum. It has a submetallic luster and a high density and is a niobate of iron and manganese, containing tantalate of iron. This mineral group was first found in Haddam,...
. They also found rhenium in gadolinite
Gadolinite
Gadolinite, sometimes also known as Ytterbite, is a silicate mineral which consists principally of the silicates of cerium, lanthanum, neodymium, yttrium, beryllium, and iron with the formula 2FeBe2Si2O10...
and molybdenite
Molybdenite
Molybdenite is a mineral of molybdenum disulfide, MoS2. 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 atoms sandwiched between sheets of sulfur atoms...
.
In 1928 they were able to extract 1 gram of the element by processing 660 kg of molybdenite.
Technetium
The same team was also involved in the discovery of technetiumTechnetium
Technetium is the chemical element with atomic number 43 and symbol Tc. It is the lowest atomic number element without any stable isotopes; every form of it is radioactive. Nearly all technetium is produced synthetically and only minute amounts are found in nature...
. They reported the discovery of element 75 and element 43 in 1925 and named element 43 masurium (after Masuria
Masuria
Masuria is an area in northeastern Poland famous for its 2,000 lakes. Geographically, Masuria is part of two adjacent lakeland districts, the Masurian Lake District and the Iława Lake District...
in eastern Prussia
Prussia
Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...
, now in Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
, the region where Walter Noddack's family originated). The group bombarded columbite with a beam of electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s and deduced element 43 was present by examining X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
diffraction spectrogram
Spectrogram
A spectrogram is a time-varying spectral representation that shows how the spectral density of a signal varies with time. Also known as spectral waterfalls, sonograms, voiceprints, or voicegrams, spectrograms are used to identify phonetic sounds, to analyse the cries of animals; they were also...
s. The wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
of the X-rays produced is related to the atomic number by a formula derived by Henry Moseley
Henry Moseley
Henry Gwyn Jeffreys Moseley was an English physicist. Moseley's outstanding contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number. This stemmed from his development of Moseley's law in X-ray spectra...
in 1913. 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 it was dismissed as an error for many years.
In 1998, John T. Armstrong of the National Institute of Standards and Technology
National Institute of Standards and Technology
The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...
performed computer simulations of the 1925 experiments and obtained results quite similar to those reported by the Noddack team. He claimed that this was further supported by work published by David Curtis of the Los Alamos National Laboratory
Los Alamos National Laboratory
Los Alamos National Laboratory is a United States Department of Energy national laboratory, managed and operated by Los Alamos National Security , located in Los Alamos, New Mexico...
measuring the (tiny) natural occurrence of technetium. Noddack's experimental results have never been reproduced, and they were unable to isolate any element 43. Debate still exists as to whether the 1925 team discovered element 43.
Discovery of element 43 was finally confirmed by a 1937 experiment in Sicily.