Otto Emil Hahn (* March 8th, 1879 in Frankfurt am Main) is a German Chemist and a Pioneer of Radiochemistry. Between 1905 and 1921, he discovered many Isotopes, in 1909 the radioactive Recoil, in 1917 the Element Protactinium, and in 1921 the nuclear isomery of „Uran Z“. Furthermore, he was responsible for the discovery and the radiochemical proof of fission of Uranium (End of 1938) and of Thorium (early 1939). Which implied that nuclear bombs were realiseable in Practice.
In 1912, Hahn got the Leadership of the radiochemical department in the newly created Kaiser-Wilhelm-Institut (KWI) for Chemistry in Berlin-Dahlem.
In the First World War, he was a Member of the - lead by Fritz Haber - Special unit for chemical warfare.
As soon as 1924, Hahn got the appointment for Ordentliches Mitglied (regular member) of the Preußische Akademie der Wissenschaften in Berlin (after being proposed by Albert Einstein, Fritz Haber, Max Planck, Wilhelm Schlenk, and Max von Laue).
Hahn's first Monography from 1926, published in the Springer-Verlag (not related to Axel Springer), called Was lehrt uns die Radioaktivität über die Geschichte der Erde? (What does radioactivity teach us about the history of Earth?), became a Standard work soon after publication, and in which Hahn fully confirmed the - so far not yet generally accepted and controversial - Theory of continental drift by Alfred Wegener.
Early 1934, Hahn declared - because of Solidarity with fired Jewish colleagues - him leaving the faculty of the Universität Berlin.
He helped his Jewish colleague Lise Meitner to emigrate illegally from Nazi Germany on July 13th, 1938.
During the war, he worked – under bad working conditions caused by the war – on the fission reactions of Uranium.
On March 22th in 1913, he married Edith Junghans in her birth city of Stettin. In 1922, they had their only son Hanno Hahn.