Potassium Tetraoxalatouranate IV

Potassium tetraoxalatouranate(IV) 5-hydrate has been prepared by the reaction of a potassium oxalate solution with an excess of uranium(IV) oxalate 6-hydrate.This excess prevents contamination of the product by potassium oxalate, since both potassium tetraoxalatouranate(IV) and potassium oxalate are precipitated from aqueous solution by absolute alcohol. 

A solution of 5 g. (0.027 mol) of potassium oxalate 1-hydrate in 20 ml. of water is added to a slurry of 6 g. (0.014 mol) of uranium(IV) oxalate 6-hydrate in 50 ml. of water. The reaction is complete after the mixture has been heated on a steam bath for 1 hour. The dark green filtrate is treated with 200 ml. of absolute alcohol, which is added drop by drop from a separatory funnel while the mixture is stirred. J Small light green crystals are obtained, which are quickly dried by washing them several times with absolute alcohol and finally with ether. To avoid oxidation, potassium tetraoxalatouranate(IV) is stored in a desiccator over phosphorus (V) oxide. 

At 17° the solubility of potassium tetraoxalatoura-nate(IV) 5-hydrate is 21.73 g. per 100 g. of water. The salt is only very slightly soluble in alcohol-water mixtures. Addition of barium ions to water solutions results in 

Dehydration of K4[U(C204)4]-5H20 at 200° for several hours yields the 1-hydrate longer heating (for several days) at this temperature causes decomposition and oxidation. 

Aluminum bromide, S3mthesis 7 Hexamminenickel(II) bromide and iodide, synthesis 52 Carbon tetraiodide, synthesis 8 Germanium(II) iodide, synthesis 17 

The procedure described below represents an improvement in the synthesis of Marchi, published in an earlier volume of Inorganic Syntheses. The earlier procedure produces a product which has a C2O4 U ratio of about 3.75. An analysis of a typical preparation is Calcd. U, 28.46 C2O4, 42.08. Found U, 29.73, 29.63 C2O4, 40.76, 40.43. A purer product can be obtained by dissolving the initial product in a solution of potassium oxalate and oxalic acid, followed by precipitation with ethanol. The concentration of alcohol specified below does not cause precipitation of potassium oxalate, potassium hydrogen oxalate, or oxalic acid. 

Inorganic Syntheses, Volume VIII Edited by Henry F. Holtzclaw, Jr. 1966 by McGraw-Hill Book Company, Inc. 

Dichlorobis(2,4-pentanedionato)titanium(IV), synthesis 10 Tris(2,4-pentanedionato)zirconium(IV) chloride, synthesis 11 Phenyllead(lV) azides (includes triphenyllead chloride and diphenyllead dichloride), synthesis 15 Diphenyl phosphorochloridite, synthesis 17 Mercapto derivatives of chlorocyclophosphazenes, synthesis 21 (Trichlorophosphoranylidene)amidophosphoryl dichloride, synthesis 22 

Trichloro[(trichlorophosphoranylidene)amino]phosphorus(V) hexachlorophosphate, synthesis 23 Imidodisulfuric acid chloride, synthesis 26 Dialkylsulfamoyl chlorides, synthesis 27 Dialkylamides of (trichlorophosphoranylidene)sulfaraic acid, synthesis 29 

Bis(trichlorophosphoranylidene)sulfamide, synthesis 30 Tris(l,l,l-trifluoro-2,4-pentanedionato)chromium(lII), synthesis 35 

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Potassium tetradecaehlorotritung-state(III), K5W3CU4, 6 149,153 Potassium tetrafluoroborate, 1 24 Potassium tetraoxalatouranate(IV), 3 169... 

Tris(2,4-pentanedionato)molybdenum(III), synthesis 39 Potassium tetraoxalatouranate(IV), synthesis 40 Trifluoromethyl hypofluorite, synthesis 42 Bis(ethylenediamine)dioxorhenium(V) chloride, bis(ethylene-diamine)oxohydroxorhenium(V) perchlorate, and bis(ethyl-enediamine)dihydroxorhenium(V) hexachloroplatinate(IV), synthesis 44... 

Uranium(lV) oxalate, synthesis 45 Potassium tetraoxalatouranate (IV), synthesis 46 Barium thiocyanate, synthesis 5 Potassium octacyanomolybdate (IV) 2-hydratc, synthesis 43 Bis(lV,lV -disallcylalethylenedia-mine)-/t-aquodicobalt(II), synthesis 53... 

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