Metals transuranium elements

In this process, uranium metal is electrodeposited at the cathode, while plutonium and other transuranium elements remain in the molten salt as trichlorides. Plutonium is reduced in a second step at a metallic cathode to produce Cd—Pu intermetallics. The refined plutonium and uranium metals can then be refabricated into metallic fuel (137). 

Using the elements mentioned in Section 22-13, induced radiation and the artificial transmutation of elements occur with both light elements, like the nonmetals 3H, 12C and 170 as well has heavier elements, like 97Tc, mFr, 210At and 239U, which can be metals, metalloids or nonmetals. Transuranium elements, i.e. the elements with atomic numbers greater than 92 (uranium), must be prepared by nuclear bombardment of other elements. 

Protactinium dipnictides (X = As, Sb) have been synthesized by reaction of As or Sb vapour with metal hydride at 400-700 Pa3As4 was obtained by thermal dissociation of PaAs2 at 840 °C, Pa3Sb4 from the corresponding dipnictide at 1200 °C. Monopnictides of protactinium were not obtained by thermal dissociation of higher compounds. The diantimonides of the transuranium elements Np, Pu, Am dissociate between 700-800 °C into the monocompounds. Monopnictides of the higher transuranium elements have been obtained at the pg scale with and 0 by thermal dissociation. 

The XPS valence band spectra for the dioxides of the transuranium elements (from Np to Bk) have been presented in an extensive and pioneering work that also includes core level spectra and has been for a long time the only photoemission study on highly radioactive compounds. High resolution XPS spectra (AE = 0.55 eV) were recorded on oxidized thin metal films (30 A) deposited on platinum substrates with an isotope separator. (The oxide films for Pu and the heavier actinides may contain some oxides with lower stoichiometry, since starting with Pu, the sesquioxides of the heavier actinides begin to form in high vacuum conditions.)... 

BERKELIUM. [CAS 7440-40-6]. Chemical element, symbol Bk, at. no. 97, at wt. 247 (mass number of the most stable isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. All isotopes of berkelium are radioactive all must be produced synthetically. The element was discovered by G.T. Seaborg and associates at the Metallurgical Laboratory of the University of Chicago in 1949. At that time, the dement was produced by bombarding 241 Am with helium ions. 4i Bk is an alpha-emitter and may be obtained by alpha-bombardment of ,4Cm. 245Cm. or 246Ciu. Ollier nuclides include those of mass numbers 243—246 and 248-250. Probable electronic configuration ... 

EINSTENIUM. CAS 7429-92-71. Chemical element symbol Es, at. no. 99. at. wt. 254 (mass number of the most stable isotope), radioactive metal of the Actinide series, also one of the Transuranium elements. Both einsteinium and fermium were formed tit a thermonuclear explosion that occurred in the South Pacific in 1952. The elements were identified by scientists from the University of California s Radiation Laboratory- the Argonnc National Laboratory, and the I. os Alamos Scientific Laboratory. It was observed that very heavy uranium isotopes which resulted from the action of the instantaneous neutron dux on uranium (contained in the explosive device) decayed to form Es and Fm. The probable electronic configuration of Es is... 

LAWRENCTUM. CAS 22537-I9-5. Chemical element, symbol Lr. at. no. 103. at. wl. 257 (mass number ol known isotope), rudiouclivc metal of the Actinide series, also one of the Transuranium elements. ""Lr was identified in 1961 by A. Ghiorso. T. Sikkelaiul. A. Larsh. and K. Latimer at the University of California ai Berkeley. 

Keller, C. and B Erdmann Preparation and Properties of Transuranium Element-Noble Metal Alloy Phases, Proc. 1972 Moscow Symp. Chem. Transuranium Elements, 1976. 

Plutonium was the second transuranium element to be discovered The isotope 2 sPu was produced in 1940 by Seaborg, McMillan, Kennedy, and Wahl at Berkeley, California hy deuteron bombardment of uranium in a 150-cm cyclotron. Plutonium exists in trace quantities in naturally occurring uranium ores. The metal is silvery in appearance, but tarnishes to a yellow color when only slightly oxidized. A relatively large piece will give off sensible heal as the result of alpha decay. Large pieces are capable of boiling water. 

Despite the extremely low concentrations of the transuranium elements in water, most of the environmental chemistry of these elements has been focused on their behavior in the aquatic environment. One notes that the neutrality of natural water (pH = 5-9) results in extensive hydrolysis of the highly charged ions except for Pu(V) and a very low solubility. In addition, natural waters contain organics as well as micro- and macroscopic concentrations of various inorganic species such as metals and anions that can compete with, complex, or react with the transuranium species. The final concentrations of the actinide elements in the environment are thus the result of a complex set of competing chemical reactions such as hydrolysis, complexation, redox reactions, and colloid formation. As a consequence, the aqueous environmental chemistry of the transuranium elements is significantly different from their ordinary solution chemistry in the laboratory. 

Colloids are always present in natural waters containing the transuranium elements. (Colloids are defined as particles with sizes ranging from 1 to 450 nm. These particles form stable suspensions in natural waters.) Colloids of the transuranium elements can be formed by hydrolysis of transuranium ions, or by the sorption of transuranium elements on the naturally occurring colloids. The naturally occurring colloids include such species as metal hydroxides, silicate polymers, organics (such as humates), and the like. The mobility of the transuranium elements in an aquifer is determined largely by the mobility of its pseudocolloids, that is, those colloidal species formed by the adsorption of the transuranium ions upon the naturally occurring colloids. 

The M(OR) derivatives are known now for almost all the elements of the Periodic Table (including the transuranium elements and Xenon). They are formal analogs of hydroxides but possess much higher thermal stability. Their properties are determined not only by the electronegativity of the metal atom but also by the nature of the radical — its ramification and the acidity of the corresponding alcohol, which provides their various properties. From this point of view they can be subdivided into the following groups of compounds ... 

The lanthanides and actinides, along with the rest of the transuranium elements, are all metals. Although they are listed apart... 

Among the elements known before transuranium elements started to be synthesized in 1940, uranium has a unique characteristic, the extreme stability of the triatomic uranyl ion OUO+z. Not only are the numbers of uranium(VI) compounds larger than of U(IV), and far larger than of the two other oxidation states U(V) and U(III) known from non-metallic compounds, but until the preparation of UOFj discussed below, the only two U(VI) compounds known to contain less than two oxygen atoms per uranium atom were the octahedral molecules UFe and UQ6. 

An unusual route used for several of the transuranium elements is a microscale reaction of the metal trichlorides with molten BeCp2 at 65 °C. 

Transition metals several series of elements in which inner orbitals (d or / orbitals) are being filled. (12.13 18.1) Transuranium elements the elements beyond uranium that are made artificially by particle bombardment. (21.3)... 

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