Chloride uranyl

Submitted by Joseph A. Leaby and John F. Suttle Checked by Henhy R. Hoekstha  

Uranyl chloride is a bright yellow substance which crystallizes in the orthorhombic system. The compound is only slightly volatile in oxygen or chlorine below 500°, and volatility is appreciable only above 775°. It decomposes in vacuo above 450° to give chlorine and the oxides U02 and UgOg. Uranyl chloride is very hygroscopic and dissolves extensively in water. The compound is soluble in polar organic solvents such as acetone and the alcohols but does not dissolve in less polar solvents such as benzene. Its aqueous solutions are both thermally and photo-chemically unstable. A number of hydrates and addition compounds with halides and amines have been described. 

National Nuclear Energy Series, Div. VII, Vol. 5, Part 8, pp. 577-587, McGraw-Hill Book Company, Inc., New York, 1951. 

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One of the first examples of photodimerization of an a,/3-unsaturated carbonyl was that of dibenzylideneacetone reported by Ciamician and Silber. Direct irradiation of this compound in ethanol or in isopropanol/benzene solution yields cyclobutane (66), although irradiation in the presence of uranyl chloride as sensitizer results in (67)(81) ... 

Dai, S., Shin, Y. S., Toth, L. M., Barnes, C. E., Comparative UV-Vis studies of uranyl chloride complex in two basic ambient-temperature melt systems The observation of spectral and thermodynamic variations induced via hydrogen bonding, Inorg. Chem., 36,4900-4902, 1997. 

G. Prins, Investigations on Uranyl Chloride, its Hydrates, and Basic Salts, Reactor Center Nederlands, RCN-186, 1973 and refs, therein. 

Tetrammino-uranyl Chloride, [UOa(XHs)JCl2.C2H10O, is obtained as a deep orange-red powder on treating the diammino-ether compound with liquid ammonia. It decomposes above 10° C. with loss of ammonia. Uranium tetrachloride in the dry state absorbs ammonia gas at ordinary temperature rise in temperature occurs, and a compound of composition [3U(XH3 )4]C1 is produced.3... 

Selenium and tellurium form similar compounds and so also do molybdenum, tungsten, and uranium, as well as chromium. Molybdyl, tungstyl, and uranyl chlorides... 

Uranium(VI) dioxydichloride, 5 148 Uranium (VI) hydrogen dioxyortho-phosphate 4-hydrate, 6 150 analysis of, 5 151 Uranium(IV) oxalate, 3 166 Uranium (IV) oxide, formation of, by uranyl chloride, 6 149 Uranium (IV) (VI) oxide, U3Oa, formation of, by uranyl chloride, 5 149... 

Uranyl chloride, 5 148 Uranyl orthophosphate 4-hydrate, U02HP04-4H20, 5 150 analysis of, 5 151 Urazine (4-aminourazole), 4 29 from carbohydrazide, 4 30 from carb ohydrazide-V-carb ox-amide, 4 31 salts of, 4 31 Urazole, 5 52... 

Invariably hydrolytic instability of lanthanide Por complexes, particularly that observed for the larger lanthanide elements, negatively influences their prospective application in terms of biomedicine (Sect. 7.4). As a response to this problem, larger porphyrin-like or expanded porphyrins , the so-called texaphyrins (Tx), have been examined by Sessler et al. [246]. The motivation, that expanded systems better accommodate larger ions, was previously demonstrated in a uranyl superphthalocyanine (SPc) complex [247], This SPc-complex contains an expanded, cyclic five-subunit pentakis(2-iminoisoindoline) which is formed by a template reaction of o-dicyanobenzene with anhydrous uranyl chloride. The uranium is displaced by only 0.02 A from the mean N5-plane. 

Table 2. Electronic origins (all in cm-1) at very low temperatures in crystalline caesium and rubidium uranyl chloride, caesium uranyl nitrate and sodium uranyl acetate. The quantum number Q characterizing many-electron states in linear chromophores (subject to perceptible relativistic effects) may correspond to two energy levels because of the 4 or 6 ligating atoms in the equatorial plane...

Principle of Separation. Uranium as the U02+ ion in strong chloride solutions forms an anionic chloride species such as U02C13 thorium does not. If a solution in which the chloride ion has been adjusted to form the uranyl chloride complex is passed through a cation exchange column, the uranium passes through the column and cationic Th+4 is absorbed. After the column is washed to insure that no uranium remains, the absorbed thorium is complexed with oxalate ions to form an anion and is released from the column. Although thorium generally is precipitated with oxalate ions, with excess quantities of oxalate it forms a soluble anionic species. The mass of thorium in this experiment is extremely low relative to that of oxalate and will not form a precipitate. 

Uranyl chloride, UO2CI2, reacts on heating with o-phthalodinitrile to form a so-called superphthalocyanine complex with 2-1-5 coordination (Figure 11.4) other metals (lanthanides, Co, Ni, Cu) react with this, forming a conventional phthalocyanine, so that the uranyl ion has an important role in sustaining this unusual structure. 

The apparent contradiction between the empirical stoichiometry and the spectral characteristics of these new uranyl complexes was finally resolved by X-ray crystallography. Specifically, a single crystal X-ray structural analysis of the blue-black material formed from the reaction of the anhydrous uranyl chloride and o-dicyanobenzene [112] (Figures 22 and 23) revealed that the complex obtained was in fact an expanded five-subunit superphthalocyanine macrocycle in which a pentagonal bipyramidal coordination geometry pertains about the centrally-bound uranium atom. 

Kalinich, J.F., Ramakrishnan, N., Villa, V., McClain, D.E. (2002). Depleted uranium-uranyl chloride induces apoptosis in mouse J774 macrophages. Toxicology 179 105-14. 

Miller, A.C., Blakely, W.F., Livengood, D., Whittaker, T., Xu, J., Ejnik, J.W., Hamilton, M.M., Parlette, E., John, T.S., Gerstenberg, H.M., Hsu, H. (1998a). Transformation of human osteoblast cells to the tumorigenic phenotype by depleted uranium-uranyl chloride. Environ. Health Perspect. 106 465-71. 

URANYL CHLORIDE see URAOOO URANYL FLUORIDE see UQAOOO URANYL NITRATE (soHd) see URA200 URANYL NITRATE HEXAHYDRATE see URSOOO URANYL NITRATE HEXAHYDRATE, solution (DOT) see URSOOO... 

Although uranium tetrachloride is highly soluble in water, it is easily hydrolyzed and oxidized into less soluble uranyl chloride and insoluble... 

Miller AC, Blakely WF, Livengood D, et al. 1998b. Transformation of human osteoblast cells to the tumorigenic phenotype by depleted uranium-uranyl chloride. Environ Health Perspect 106 465-471. 

In a much earlier patent, the removal of organics from exhaust gases by oxidation over a supported uranium oxide catalyst was reported by Hofer and Anderson [39]. The catalyst was 4% U3O8 supported on alumina spheres. The authors used the incipient wetness technique to impregnate alumina with uranyl nitrate solution. In this case the catalyst precursors were calcined at 700°C for 3 h to decompose the uranium salt. The use of other uranium compounds as starting materials was mentioned and these included uranyl acetate, uranium ammonium carbonate and uranyl chloride. The alumina-supported catalyst had a surface area of ca 400m g and further added components, such as copper, chromium and iron, were highlighted as efficient additives to increase activity. 

The recovery of uranium from hydrochloric acid solutions and its concentration are described in [43]. In this operation, 10 M HCl solution containing uranium traces is treated with strongly basic anion exchanger. Upon washing the ion exchanger with water the effluent of uranyl chloride at a concentration level as large as 200 g/L uranium is obtained. 

Uranium Difluoride, UFg.—The solution obtained after electrolysis of an aqueous solution of uranyl chloride acidified with hydrochloric acid yields, on addition of excess of hydrofluoric acid, a green precipitate of composition UF2.2H,0. ... 

It is formed in solution by oxidising uranous chloride with nitric acid by dissolving uranic oxide in concentrated hydrochloric acid or by adding barium chloride to a concentrated solution of uranyl sulphate until precipitation is complete. Its aqueous solution on evaporation yields the monohydrate, UOaClj.HaO." The solution is unstable at ordinarj temperatures and slowly deposits uranic hydroxide, which after a time partly redissolves. The uranyl chloride may be reduced in solution to black uranous oxide by the action of magnesium or aluminium powder. The densities of aqueous solutions of uranyl chloride have been determined as follows ... 

A saturated solution of uranyl chloride in hydrochloric acid when cooled to —10° C. yields yellow crystals of an unstable hydrochloride, U02Cl2.HC1.2H20. The compound may also be obtained by the action of hydrochloric acid on uranyl nitrate. ... 

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