Tris uranium chloride

Compounds of the type MCpsX, where M is an actinide element in the iv oxidation state and X is an anion, have been prepared in large numbers and with a great variety of anions. Evidence has been adduced that the uranium tris(cycIopentadienyI) chloride ionizes in water to form the UCp3 and Cl" ions. Replacement of anions can readily be effected in such solutions. Anions that can be introduced include not only the common halides, sulfate, perchlorate, nitrate. 

Fig. 20.15 One unit cell of the structure of tris indenyl)uranium chloride. Uranium atoms are at the center of each molecule the lone atom attached to uranium is a chlorine. Reproduced, with permission, from ref. 488, copyright by the American Chemical Society.)...

Tri-n-butyl phosphate, ( -C4H9)3P04. This solvent is useful for the extraction of metal thiocyanate complexes, of nitrates from nitric acid solution (e.g. cerium, thallium, and uranium), of chloride complexes, and of acetic acid from aqueous solution. In the analysis of steel, iron(III) may be removed as the soluble iron(III) thiocyanate . The solvent is non-volatile, non-flammable, and rapid in its action. 

The question of the mode of bonding of the cyclopentadienyl rings in complexes of the type U(C5Hs)sX was settled by the structural determination of tris(ben-zylcyclopentadienide)uranium(IV) chloride (69). The structure as viewed down... 

Uranium forms two stable fluorides, UF4 and UFe. When metal is heated with fluorine gas, hexafluoride, UFe, is produced. Heating powdered metal with hydrogen fluoride gas at 350°C yields tetrafluoride, UF4. Powdered metal is obtained by thermal decomposition of trihydride, UH3. Uranium combines with chlorine at elevated temperature (at about 500°C) to form a mixture of various chlorides namely, the tetrachloride, UCI4, pentachloride, UCI5, and hexachloride,UCl6. Heating the metal with bromine vapor at 650°C forms tetrabromide, UBr4. Uranium also forms tri-and pentabromides. With... 

Certain long-chain alkylammonium salts, notably tricaprylmethyl-ammonium chloride (Aliquat 336-S) and tri-/so-octylamine hydrochloride (TIOA) are liquids, sometimes referred to as liquid anion exchangers, which can form extractable ion-pairs or aggregates with anionic metal complexes in the same way, e.g. in sulphuric acid solution uranium is extracted as 2(TIOA—H+), UOtfSOn ... 

The X-ray structure of CpsUCl reveals a distorted tetrahedral uranium coordination geometry as shown in (2) with three -Cp ligands at 2.74( 1) A from the metal center and the U-Cl bond (2.559(16) A) coincident with the molecular threefold axis. This type of structure is essentially identical for all CpsUX derivatives. A more accurate X-ray diffraction study of tris(benzylcyclopentadienyl)uranium(IV) chloride gave an average U-Crmg distance of 2.733(1) A and a U-Cl distance of 2.627(2) A. ... 

The tris(cyclopentadienyl)thorium-, -uranium- and -plutonium chlorides are best prepared from TlCp in dimethoxyethane Np(Cp- )3Cl is formed in the Be(Cp)2 melt reaction . Analogous complexes containing bromide, iodide and/or indenyl ligands are prepared from K[Cp] or K[indenyl] and the appropriate MX4 compound (see Table 2). 

Amine Extraction. Tri-n-octylamine was prepared by repeated washing of tri-n-octylammonium chloride with IN NH4OH followed by washing with water. Uranium extraction experiments were performed with U-233 tracer which contained a small amount of hydrochloric acid. Successive backwashing of extracts with acetic acid was used to eliminate the chloride. Np-237 and Pu-239 were oxidized with ozone and back-washed two or three times to eliminate lower oxidation states. 

FIGURE 31.17 Schemes of the highly selective ligand for uranium recovery from seawater, (a) The hexacarboxylate Ugand (b) after reaction with tri-octyl methyl ammonium chloride. (Reproduced from Tabushi, I., Kobuke, Y., Nakayama, N., Aoki, T., and Yashizawa, A., Ind. Eng. Chem. Prod. Res. Dev., 23, 445, 1984. With permission.)... 

Separation by solvent extraction Uranium can be extracted from aqueous solutions using extraction agents into the solvent phase, from which it can be stripped. The extraction agents used are phosphorus compounds such as di-(2-ethylhexyl)-phosphate, tri-n-butyl-phosphate and tri-n-octylphosphine oxide as well as primary, secondary and tertiary amines in salt form or as quaternary ammonium salts. The extraction agents are diluted with inert hydrocarbons, preferably kerosene, to concentrations of 4 to 10% by volume. The solubility of the amine salts, particularly the hydrogen sulfates, chlorides and nitrates is increased by adding long chain alcohols (e.g. isodecanol). 

The donor action of [NOs]" as an anionic ligand towards thorium(iv) and uranium(iv) in the presence of trimethylphosphine and tris(dimethylamino)phosphine oxide in aqueous media has been found to be very similar. The larger nitrate ion was observed to form more stable species with thorium than the chloride ion whereas in the uranium(iv) case both complexes formed equally readily. A study of the sulphate complexes of uranium(iv), neptunium(vi) and plutonium(vi) in HCIO4-H2SO4 solution showed the stability constants to follow the order U[Pg.453]

AETHYLALKOHOL (German) (64-17-5) Forms explosive mixture with air [flash point 55°F/13°C 68°F/20°C (80%) 72°F/22°C (60%) 79°F/26°C (40%)]. Reacts, possibly violently, with strong oxidizers, bases, acetic anhydride, acetyl bromide, acetyl chloride, aliphatic amines, bromine pentafluoride, calcium oxide, cesium oxide, chloryl perchlorate, disulfuryl difluoride, ethylene glycol methyl ether, iodine heptafluoride, isocyanates, nitrosyl perchlorate, perchlorates, platinum, potassium-tert-butoxide, potassium, potassium oxide, potassium peroxide, phosphorus(III) oxide, silver nitrate, silver oxide, sulfuric acid, oleum, sodium, sodium hydrazide. sodium peroxide, sulfinyl cyanamide, tetrachlorosilane, -tri-azine-2,4,6-triol, triethoxydialuminum tribromide, triethylaluminum, uranium fluoride, xenon tetrafluoride. Mixture with mercury nitrate(II) forms explosive mercury fulminate. Forms explosive complexes with perchlorates, magnesium perchlorate (forms ethyl perchlorate), silver perchlorate. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

Scheme 1 Some reactions of tris (cyclopentadienyl) uranium (IV) chloride...

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