August 17 is Walter Noddack’s birthday. Noddack was a German chemist who co-discovered the element rhenium.
Noddack was investigating platinum ores with Ida Tacke, who would become Ida Tacke Noddack and Otto Berg. They had hoped to fill in some of the holes in the Periodic table, namely the missing elements 43 and 75. On Mendeleev’s Table, those positions were marked as eka-manganese and div-manganese as placeholders for currently unknown elements.
The mineral ores columbite, molybdenite, and gadolinite all are sources of elements that appear around the missing elements. They hoped these contained trace amounts of what they were searching for. They analyzed each of them using emission and x-ray spectroscopy and found evidence of one of the unknown elements. After processing nearly 600 kilograms of molybdenite, they were able to isolate 1 gram of rhenium.
After successfully filing one Periodic Table hole, they moved on to find element 43. They hoped it would be easier to discover than rhenium since it should have similar chemical properties but appears earlier in the Periodic Table. Previous attempts at finding this element centered around platinum ores. Noddack’s team searched in the platinum ore called columbite. They bombarded their samples of columbite with electrons and analyzed the results using x-ray spectroscopy. They discovered a faint peak at the wavelength that would be associated with element 43. Believing they had discovered the missing element, they announced their discovery and named the element masurium after the Masuria region of Eastern Prussia.
Unfortunately, no one could reproduce their results and their claim was discounted as an error. Eka-manganese would remain unknown until 1936 when Emilio Segrè and Carlo Perrier bombarded molybdenum with neutrons using a particle accelerator. Their samples contained a radioactive isotope of element 43 which they named technetium.
Other Notable Science Events for August 17
2005 – John Norris Bahcall died.
Bahcall was an American astrophysicist who worked on the solar neutrino problem where there was a large difference between the number of neutrinos measured from the Sun and the number predicted by theory. His work on neutrino detection would lead to a Nobel Prize for Raymond Davis Jr. and Masatoshi Koshiba in 2002. He was also involved in the development of the Hubble Space Telescope.
1970 – Venera 7 Spacecraft Launched
NASA
Venera 7 was a Soviet probe designed to land on the surface of Venus. It was launched from the Baikonur launch site and would arrive at Venus in December 1970. It entered the atmosphere and managed to reach the surface, becoming the first spacecraft to land and transmit data from another planet. The lander transmitted data for 20 minutes from the surface before going silent. The data showed an outside temperature of 475 °C (887 °F) with a pressure 90 times the pressure on Earth.
1969 – Otto Stern died.
Wikimedia Commons
Stern was a German physicist who was awarded the 1943 Nobel Prize in Physics for the discovery of the magnetic moment of the proton and the development of the molecular beam. A molecular beam is any stream of molecules moving in the same direction in a vacuum.
He also worked with Walther Gerlach to prove the quantization of spin.
1893 – Walter Noddack was born.
1886 – Aleksandr Mikhaylovich Butlerov died.
Butlerov was a Russian chemist who first stated the importance of a chemical’s structure. He stated that a chemical’s nature was determined not only by its components but the arrangement of those components. He was also the first to recognize double bonds in chemical structures. Butlerov discovered formaldehyde and the formose reaction where sugars are formed from formaldehyde.
1877 – Mars moon Phobos discovered.
American astronomer Asaph Hall discovered the second of two small moons of Mars. He discovered the other moon a couple days prior. Hall named the small moons Phobos and Deimos after the sons of Ares, the God of War in Greek mythology. Ares is the Greek name of Mars in Roman mythology.