Uranium IV Chloride

Submitted by John A. Hermann and John F. Suttle Checked by Henry R. HoEKSTRAf 

Some of these reactions take place in the vapor phase at elevated temperatures others are run in the liquid phase. The procedure involving hexachloropropene outlined here is typical. Although many such reactions yield some contaminating uranium(V) chloride, this contamination is minimized by differences in solubility relationships and by the thermal instability of uranium(V) chloride. 

Uranium(IV) chloride forms dark green octahedral crystals of tetragonal symmetry (m.p. 590°). The vapor pressure of the solid (350 to 505°) is given by the expression 

The liquid boils at 792° (1 atm.). The heat of formation of the solid is 250.9 0.6 kcal./mol at 0°. Uranium(IV) chloride dissolves readily in water and in polar organic solvents but is insoluble in nonpolar solvents such as hydrocarbons and ethyl ether. Its solutions have a number of characteristic and sharply defined light-absorption bands. The compound oxidizes in air and decomposes in aqueous solution. It is best preserved in a sealed container in a dry, inert atmosphere. 

Katz and E. Rabinowitch The Chemistry of Uranium, Part I, National Nuclear Energy Series, Div. VII, Vol. 5, Part 8, p. 461, McGraw-Hill Book Company, Inc., New York, 1951. 

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Uranium(IV) chloride adducts of Ph2SO have been isolated (73) of the type [U(Ph2S0)2Cl4]-nH20, and infrared measurements show the sulfoxide to be O-bonded. Analogous complexes of diphenyl sulfone could not be synthesized (251). 

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... 

Preparation of Uranium(IV) Chloride. Perform the experiment in a fume cupboard ) a. Assemble an apparatus as shown in Fig. 134. To purify the hydrogen more completely from impurities, CO,... 

Uranium (V) chloride, formation of, in preparation of uranium (IV) chloride, 5 144... 

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. ... 

Synonyms UN2977 uranium fluoride (fissle) Uranium (IV) chloride Uranium oxyfluoride uranium fluoride oxide bis(Acetate-B) dioxouranium bis(Nitrate-O) dioxouranium hexahydrate... 

The method used by Hermann and Suttle for the preparation of uranium(IV) chloride can be conveniently extended... 

Figure 6 Absorption spectra of uranium(IV)-chloride complexes in solution and the anion exchanger in equilibrium with this solution (from Ref 11) coordination of the resin phase complex (from Ref 29) A 10 M HCl solution of U(IV) B AG 1-X8 equilibrated with solution A O experimental plot -------theo-...

A solution of uranium (IV) chloride and an olefin (stilbene, diphenylethylene, or acenaphthylene) in tetrahydrofuran (THF) can be reduced by pulse radiolysis to give U(III) (246). The reaction may proceed through an anionic complex. 

UCI4, Uranium(IV) chloride, 21 187 UF2O2, Uranium(VI), diiluorodioxo-,... 

A solution of [f/ -l,3-bis(trimethylsilyl)cyclopentadienyl]lithium is prepared in situ, using the procedure described in Section 33.A, from butyllithium (IS.OmL of a 1.5 M solution in C6H14, 29 mmol) and bis(trimethylsilyl)cyclo-pentadiene (5.89g, 28 mmol) in THF (lOOmL). This solution is added dropwise during h to a stirred, cooled (0°Q solution of uranium(IV) chloride (5.45g, 14mmol) in THF (lOOmL). The mixture is stirred at 25°C for 12h. Removal of the solvent at 25 °C and lOtorr affords a sticky brown residue this residue is warmed to 60°C at 10 torr. The brown involatile solid is extracted into warm toluene (100 mL), and the extract is filtered. The brown filtrate is concentrated (to 50mL), then cooled to — 30°C to yield large orange-brown crystals of [UCp"2 CI2 ] (2). Yield 6.1 g (60%). Two further crops of crystals are obtained from the mother liquor (total yield, 90%). For its characterization, see Table I. 

The synthesis of compounds such as bis (778-cyclooctatetraene)uranium [urano-cene,1,2 U(CgH8)2] with high volatility has generated renewed interest in organometallic compounds of tetravalent uranium. Uranium(IV) chloride, which... 

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