Technetium, with the atomic number 43 and symbol “Tc,” is regarded as the first-ever artificially-produced element, although there are a few isotopes of technetium that are naturally occurring. It is also the lightest element on Earth, and all of its isotopes are radioactive. For its naturally-occurring isotopes, they are typically produced through spontaneous fission in thorium ore and uranium ore. In terms of its appearance, technetium has a silvery and crystalline look similar to platinum. To know more about this element, let us look at the interesting discovery of technetium.
Discovery of Technetium
When Russian chemist Dmitri Ivanovich Mendeleev showed his periodic table to the public in 1871, he left several gaps or empty spaces on its, as he believes that there are still more elements to discover on Earth. One of those empty spaces are between element 42 (molybdenum) and element 44 (ruthenium), and Mendeleev proposed that space have similar chemical properties to manganese, which is right above it. Mendeleev gave that mysterious element a placeholder name, “ekamanganese,” which means “one below manganese” in Sanskrit.
There have been many chemists who claim to have been the first to discover technetium, but there was only one official discovery that has sufficient evidence to support the claim. But before we get to the official discovery, we first need to take a look at the other studies conducted to discover technetium.
The first chemists to claim the discovery of element 43 were Walter Noddack, Ida Tacke, and Otto Berg, who published their research in 1925. According to them, they discovered element 43 by bombarding the black mineral columbite with beams of electrons, and while the process was ongoing, they found out that element 43 is present as they are taking a closer look at the X-ray emission spectrograms. The chemist then named element 43 as “masurium,” which is derived from the Polish region Masuria, where Noddack grew up. Unfortunately, after the initial tests, the chemists, as well as the groups that tried to copy the process, were unable to produce traces of technetium again, thus leading the leaders of the chemistry industry to proclaim the research erroneous. Despite being considered as a false claim, the name “masurium” stuck with element 43 for years before its official discovery in 1937. The discovery claims of the three chemists in 1925 are still being studied upon to this day to prove if they have indeed found out about technetium in that year.
The official discovery of technetium was conducted by scientists Emilio Segre and Carlo Perrier, who were studying cyclotron parts at the University of Palermo in Italy in 1937. A year before the research, Segre first visited the United States and asked cyclotron inventor Ernest Lawrence if he could be given some discarded cyclotron parts that have become radioactive. Lawrence then sent him a foil of molybdenum, a chemical element with the atomic number 42 and symbol “Mo” in the periodic table, which has served as a part of the cyclotron’s deflector.
Segre then hired his colleague Carlo Perrier to help him prove that the molybdenum found in the foil also contains the mysterious element 43. In 1937, they successfully isolated two isotopes of element 43, namely technetium-95m and technetium-97. The administration of the University of Palermo wanted the two scientists to name the new element as “panormium,” which is supposed to be derived from the university’s Latin name, “Panormus.” However, Segre and Perrier decided to call element 43 as “technetium,” a named derived from the Greek word “technitos,” meaning “artificial,” due to how they artificially produced the two isotopes. A few months later, Segre partnered with Glenn T. Seaborg to isolate a new isotope called technetium-99m, the isotope that is now used in medical diagnostic procedures.
In 1952, an astronomer by the name of Paul W. Merrill discovered a spectral signature of technetium from a light produced by S-type red giants or red stars. These red giants only have a few thousand or million years left in their life, although they are rich in technetium, which is a rare element on Earth. Merrill and the other scientists proposed that the technetium in these stars is produced by nuclear reactions, and these reactions would ultimately allow the stars to produce heavier elements that are not found in the solar system. Because of this discovery, the number of studies conducted on technetium has skyrocketed over the years, as this element is believed to be one of the keys to having a better understanding of the universe. Regardless of its importance in astronomy, technetium is still regarded as one of the most important elements in the medical field, as it is primarily used in machines or devices on nuclear medicine. One of the isotopes used in nuclear medicine is technetium-99m, which is useful as a radioactive tracer to help doctors find anomalies in several parts of the body.