The Discovery of Nuclear Fission - Good Solid Chemistry Got Things on the Right Track

Abstract

An outline of the history of fission is given covering the period between spring 1934, when for the first time uranium was fissioned by irradiation with neutrons but the fission products were erroneously attributed to transuranium elements, and winter 1938/1939, when fission was discovered by a radiochemical experiment and confirmed world-wide with a variety of methods.

Chemistry of Superheavy Elements

“…[231] The same order results from classical extrapolations of thermochemical properties down Group 7 which also predict BhO 3 Cl to be more stable and volatile than TcO 3 Cl and ReO 3 Cl. [232] If only trace amounts or single atoms are present it can safely be assumed that the species MO 3 Cl is formed with oxidizing chlorinating gases. The oxy halide compounds of Group 7 elements reflect their intermediate position between the lighter transactinides, which form volatile halides, and the highly volatile Group 8 tetroxides.…”

“…In parallel, and to compare and understand the measured distribution coefficients (K d ), theoretical model calculations [108,168] were performed to compute hydrolysis constants and complex formation constants and described these processes for Group 4 elements (M = Zr, Hf, Rf). The first hydrolysis step is described in the reaction in Equation (3). At pH > 6 the pH-dependent stepwise hydrolysis (deprotonation) process gives rise to the formation of M(OH) 5 À .…”

“…A hypothetically Th-like or Pu-like behavior of Rf was tested in AIDA with an anion-exchange resin and 8 m HNO 3 . While Th and Pu form anionic complexes, and are consequently strongly adsorbed, Rf remains in solution [123] forming cationic or neutral species-as expected for a typical Group 4 element with non-Th-like-and non-Pu-like properties.…”

“…[231] This result coincides with the value expected from empirical correlations of thermochemical properties assuming Bh is in Group 7. [232] As with the Sg oxy chloride, an empirical correlation was used for BhO 3 Cl to estimate the sublimation enthalpy: DH …”

“…Among the mistakes which led these scientists astray, were presumptions about the structure of the Periodic Table at its far end-the transuranium elements were assumed to belong to Group 7 and the following Groups. The unexpected discovery of nuclear fission [1] marked the first obstacle, and, at the same time, brought new insight and opportunities [2,3] . Soon after, the first transuranium elements, neptunium and plutonium were synthesized.…”