Uranic rays

M. Genet, The Discovery of Uranic Rays A Short Step for Henri Becquerel but a Giant Step for Science, Radiochim. Acta 70/77, 3 (1995)... 

I querel later retracted his results, however, when he discovered that a photographic plate with the same crystals showed a bright exposure spot even when the plate and the crystals were stored in a dark drawer and not exposed to simlight. Becquerel realized that the crystals themsdves were constantly emitting something (independent of whether or not they phosphoresced) that exposed the photographic plate. Becquerel concluded that it was the uranium within the crystals that was the soiuce of the emissions, and he called the emissions uranic rays. 

Uranic rays were the name given by Henri Becquerel to the radiation emitted by crystals that contained uranium. 

Becquerel s work was continued by a young Polish graduate student in Paris named Marie Sklodowska Curie (1857-1934). Curie chose the study of uranic rays as the topic for her doctoral dissertation. Rather than focus on the rays themselves, as Becquerel had, she began to search for other substances that might emit uranic rays. She was a brilliant chemist and, with the help of her husband, Pierre Curie (1859-1906), she found two other substances that emitted these rays, one of which was a previously undiscovered element. She writes, We therefore think that the substance that we have extracted. . . contains a metal previously unknown. We propose to call it polonium, after the native land of one of us. Since the Curies discovered that uranic rays were not unique to uranium, they changed the name from uranic rays to ray activity or radioactivity. By further experimentation, they deduced that radioactivity was not a product of a chemical reaction, but instead, a product resulting from changes within the atom itself. 

Soon after Becquerel s discovery, a young graduate student named Marie Sklodowska Curie (1867-1934) (one of the first women in France to pursue doctoral work) decided to study uranic rays for her doctoral thesis. Her first task was to determine whether any other substances besides uranium (the heaviest known element at the time) emitted these rays. In her search. Curie discovered two new elements, both of which also emitted uranic rays. Curie named one of her newly discovered elements polonium, after her home country of Poland. The other element she named radium, because of its high level of radioactivity. Radium is so radioactive that it gently glows in the dark and emits significant amounts of heat. Since it was clear that these rays were not unique to uranium. Curie changed the name of uranic rays to radioactivity. In 1903, Curie and her husband, Pierre Curie, as well as Becquerel were all awarded the Nobel Prize in physics for the discovery of radioactivity. In 1911, Curie received a second Nobel Prize, this time in chemistry, for her discovery of the two new elements. 

Uran-saure, /. uranic acid, -strahlen, m.pl. uranium rays, -tonbad, n. (Photog.) uranium toning bath, -tonung, /. uranium toning, uranuranig, a. uranoso-uranic, uranium(IV,VI). Uran-verbindung, /. uranium compound, -ver-starker, m. uranium intensifier. -vitriol, n. (Aftn.) johannite. 

Preparations of ionium are used as standards of a-ray activity when a more active standard than urano-uranic oxide is necessary. The production of helium from ionium has been obser ed. Uranium Xj may be used as an indicator for ionium when estimating the latter in terms of the equilibrium quantity contained in uranium minerals. ... 

The product obtained from the lithium nitrate-potassium nitrate eutectic is neither identifiable as the diuranate (U2O7 ) or uranate (UO4 ) species, nor as a mixture composed of each of these species. To date, the x-ray powder diffraction pattern has not been identified with any known compound. It is interesting to note the ratios of the alkali metals for this system, however approximately a 2 1 atomic... 

A new Tl uranate, T14U05, has been made by careful heating of T12C03 + U03 under N2.597 It dissociates above 230 °C to T120 + T12U04, and it has been characterized by X-ray powder diffraction. 

Streitwieser noticed that the HOMOs of C Hg have the correct symmetry to interact with the 5/orbitals of an actinide (or 4/of a lanthanide). This led to the preparation of the sandwich complex bis(cyclooctatetraene)uranium (uran-ocene). Uranocene is pyrophoric in air, but it thermally very robust. It forms deep green crystals which can be sublimed under vacuum. X-ray diffraction shows that the rings are parallel and eclipsed (Dg ). 

A series of crystalline compounds of substituted ammonium hexachloro-and hexabromoprotactinates(iv), thorates(iv), uranates(iv), plutonates(iv), and neptunates(iv) have been prepared and examined by x-ray powder diffraction methods, for which some structural details are available [392], as well as for Cs2UBr6 and Cs2NpBre, which are cubic [393]. 

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