Uranium spectroscopic properties

Dieke, G. H., Duncan, A. B. F. Spectroscopic properties of uranium compounds. New York McGraw-Hill 1949. 

Spectroscopic properties Photoemission from the valence band of uranium and plutonium indicates a 5 f band at the Fermi leveT (see Chap. E). 

Here, the main features of the valence band results for Th02 and UO2 will be illustrated. Since a large number of publications exists in this field (especially for uranium oxides), reference will be made only to a few selected investigations, chosen for the purpose of highlighting those aspects of the oxide bond discussed previously. A very comprehensive review of these results can be found (and references therein electronic and spectroscopic properties in Refs. 109-111). Figure 21 shows the photoemission spectrum of Th02 and UO2 up to Et = 45 eV The valence band region extends to about 10 eV. The marked difference is the appearance in UO2 of a sharp and intense peak at Et =... 

Uranium-238 emits an alpha particle to become an isotope of thorium. This unstable element emits a beta particle to become the element now known as Protactinium (Pa), which then emits another beta particle to become an isotope of uranium. This chain proceeds through another isotope of thorium, through radium, radon, polonium, bismuth, thallium and lead. The final product is lead-206. The series that starts with thorium-232 ends with lead-208. Soddy was able to isolate the different lead isotopes in high enough purity to demonstrate using chemical techniques that the atomic weights of two samples of lead with identical chemical and spectroscopic properties had different atomic weights. The final picture of these elements reveals that there are several isotopes for each of them. 

Hoard, J. L., Stroupe, J. D., Spectroscopic Properties of Uranium Gom-pounds, pp. 13-15, McGraw-Hill, New York, 1949. 

A. B. F. "Spectroscopic Properties of Uranium Compounds" McGraw-Hill New York, 1949. 

For several solids containing linear uranyl groups a detailed study of the absorption spectra has been performed by Denning and coworkers using the results of MO calculations on the UO " ion o- ). In the past few years several authors reported on the spectroscopic properties and the electronic energy level scheme of another octahedral uranium complex UFs 34-38) molecule is isoelectronic with... 

Astatine is a radioactive element that occurs in nature in uranium and thorium ores, but only to a minute extent. Samples are made by bombarding bismuth with a particles in a cyclotron, which accelerates the particles to a very high speed. Astatine isotopes do not exist long enough for its properties to be studied, but it is thought from spectroscopic measurements to have properties similar to those of iodine. 

The chemistry of uranium interacting with atmospheric components, like carbon, nitrogen, and oxygen, poses a formidable challenge to both experimentalists and theoreticians. Few spectroscopic observations for actinide compounds are suitable for direct comparison with properties calculated for isolated molecules (ideally, gas phase data are required for such comparisons). It has been found that even data for molecules isolated in cryogenic rare gas matrixes, a medium that is usually considered to be minimally perturbing, can... 

Astatine is a radioactive element that occurs in uranium ores, but only to a tiny extent. Its most stable isotope, °At, has a half-life of 8.3 h. The isotopes formed in uranium ores have much shorter lifetimes. The properties of astatine are surmised from spectroscopic measurements. Astatine is created by bombarding bismuth with alpha particles in a cyclotron, which accelerates particles to high speed. 

Because of its large size and accessibility to multiple oxidation states, uranium is capable of unprecedented reactivity and beautiful coordination complexes that caimot be achieved with transition metals or lanthanides. The exciting products highlighted here demonstrate that we have only just begim to learn the capabilities of uraniiun, and that continuous studies will be needed to determine the full realm of possibiUties. From activation of small molecules to unique magnetic properties, uranium offers a synthetic and spectroscopic challenge to coordination chemists of the future. 

The products were formulated as hexaalkyl dianions, [084]] URi . Although these compounds decompose thermally below room temperature, it proved possible partially to characterize them. Some of the spectroscopic and magnetic properties are rather unusual [2]. In reaction with tetramethylethylenediamine (TMEDA), the Li2UR6-8S complexes yield Li2UR6-7TMEDA derivatives. Sigurdson and Wilkinson [IS] also investigated pentavalent uranium chemistry ... 

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