Uranyl chloride 1-hydrate

U02(N03)2-6Hi,0 + 2HC1 UOsCU-GHjO + 2HNOs UOjCh-eHjO + 5SOCl2- UO2CI2 H2O + 5SO2 + lOHCl 

Submitted by Jack D. Hbpley, Daniel M. Mathews, and Edward S. Amis  

Anhydrous uranyl chloride has been prepared by reaction of oxygen with uranium(IV) chloride at 300° to 350°. Other procedures for preparing uranyl chloride are reaction of chlorine with uranium(IV) oxide at 500° reaction of carbon tetrachloride with uranium (VI) oxide at 290° and reaction of hydrogen chloride mth partially hydrated 

Two hundred and fifty grams, or any convenient weight depending on the weight of product desired, of pure uranyl nitrate 6-hydrate is treated with sufficient concentrated hydrochloric acid so that the salt is readily dissolved. Amounts of reagents in this preparation are not critical. The solution of the salt in the acid is evaporated by distillation until it becomes very viscous. At this point, concentrated hydrochloric acid is added in small portions and distillation continued until no brown oxides of nitrogen can be seen and until the brucine test indicates that no nitrate is present in the solution. 

Uranyl chloride 1-hydrate is a yellow powderlike material resembling powdered sulfur in appearance. The compound is very hygroscopic, takes up water vapor from the air readily, and must be handled in a dry-box. Its other properties are similar to those listed for anhydrous uranyl chloride. The monohydrate is soluble in polar solvents such as ethanol and acetone but does not dissolve in nonpolar solvents. Its aqueous solutions are stable at room temperature and its alcoholic solutions are unstable. The anhydrous compound, several hydrates, and addition compounds with halides and amines have been described. 

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See also Lithium hydroxide and lithium oxide, synthesis 1 Vanadium(II) hydroxide, synthesis 30 Uranyl chloride 1-hydrate, synthesis 41 Chlorine (CP )-labeled thionyl chloride, silicon tetrachloride, boron chloride, germanium(IV) chloride, and phos-phorus(III) chloride, synthesis 44 Inner complexes of cobalt(III) with diethylenetriamine, synthesis 56... 

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

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... 

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. 

Aquopentammine- and acido-pentamminechromium(III) salts, synthesis 36 Tripotassium enneachloroditung-state(III), synthesis 38 Uranium(IV) chloride, synthesis 39 Uranium(III) chloride, synthesis 40 Uranyl chloride, synthesis 41 Iron(II) chloride 2-hydrate, synthesis 48... 

UC15 Uranium(V) chloride, 6 144 U02 Uranium (IV) oxide, 6 149 U02C12 Uranyl chloride, 6 148 U02(C9H6N0)2 Bis(8-quinolinolo)-dioxouranium(VI), 4 101 compound with 8-quinolinol, 4 101 U02HP04-4H20 Uranyl orthophosphate 4-hydrate, 6 150 U308 Uranium (IV) (VI) oxide, 6 ... 

UCI5 Uranium (V) chloride, 6 144 UO2 Uranium (IV) oxide, 6 149 UO2CI2 Uranyl chloride, 6 148 1-hydrate, 7 146... 

Strong oxidizing acids, like nitric acid, produce stable hexavalent nranyl ions that can be extracted by suitable complex forming agents like tribntylphosphate (TBP). Uranyl compounds are generally very soluble in aqueous solutions and concentrations of several hundred grams of uranium per liter are quite common, like uranyl nitrate with solubility of 660 g L . Uranyl acetate, uranyl sulfate, uranyl chloride, and uranyl phosphate are all yellow salts and usually appear as hydrates. Uranyl fluoride, the product of hydrolysis of UFg, was discussed earlier. 

Barium Diuranate, BaUjO, is obtained by heating barium uranyl acetate, or by heating together the green oxide and barium chlorate. It is obtained in a hydrated condition when ammonia is added to mixed solutions of barium chloride and uranyl nitrate, or when excess of baryta water is added to uranyl nitrate solution. It is a deep yellow crystalline powder. 

Uranium(IV) oxalate has been prepared by the reaction of uranium(IV) chloride,sulfate, and hydroxide with a saturated solution of oxalic acid, or by the reduction of a water-soluble uranyl compound with copper, zinc, or sodium dithionite (Na2S204), followed by treatment with oxalic acid. It is prepared conveniently by the reduction of the readily available uranyl acetate 2-hydrate with sodium dithionite. 

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