Die Geschichte des Periodensystems der chemischen Elemente von den Anfängen bis zur Gegenwart. Teil 2

Nachdem im ersten Teil dieser Arbeit [12] die Geschichte des Periodensystems bis zur atomtheoretischen Deutung dargestellt wurde, behandelt der vorliegende zweite Teil die Auffüllung der Lücken in der Tabelle, die Erweiterung des Systetns durch die Transurane und die Vorhersagen ferner Transurane. Außerdem werden einige interessante Darstellungen des Periodentsystems besprochen.     

The Search for Transuranium Elements and the Discovery of Nuclear Fission

The synthesis of new, artificial elements beyond uranium was at the cutting-edge of physical research in the 1930s, and nearly half a dozen transuranium elements were reported between 1934 and 1938. Nuclear physicists and radiochemists collaborated closely, but each field introduced fundamental assumptions that proved to be false: that nuclear changes would always be small, and that transuranium elements would resemble transition elements chemically. With its surprise ending in the discovery of nuclear fission, the misguided transuranium project can be viewed as an example of the illogical progress of scientific discovery. It is also an example of an interdisciplinary collaboration that was flawed yet crucial, for although chemists and physicists both contributed to the delay in discovering fission, their collaboration was essential in leading them to it in the end.     

Spark-Source Mass Spectrometric Techniques for the Analysis of Lanthanide and Actinide Elements in Microgram and Sub-Microgram Transuranium Samples

Abstract

Lanthanide and actinide impurities in a total sample of 1 to 10 μg of transuranic matrix can be determined by employing the spark-source mass spectrograph and solution technique. A special source glove box permits safe manipulation of transuranium elements with α-emitting radioactivity up to 10¹² dpm. The minimum detection limit is about 10¹² atoms per electrode system and an exposure of 10^?8 coulomb. Relative sensitivity values for the lanthanides and actinides were established with respect to erbium, the internal standard.     

Energy Decomposition Analysis of Metal—Metal Bonding in [M2X8]2‐ (X: Cl,Br) Complexes of 5f (U,Np, Pu), 5d (W,Re, Os), and 4d (Mo,Tc, Ru) Elements.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

Ternary Rare Earth and Actinoid Transition Metal Carbides Viewed as Carbometalates.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.