Preparation of Uranium IV Chloride

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, 

Extract the boat with the substance from the quartz tube. Transfer the preparation into a weighed weighing bottle (in a dry cham- 

Write the electron configuration of the manganese atom. Give examples of compounds corresponding to the different oxidation states of manganese. Indicate the position of manganese in the electrochemical series of the metals. How does it react with water, and with solutions of acids in the cold and with heating Write the equations of the relevant reactions. 

Manganese(II) Hydroxide. 1. Take manganese(II) chloride as the starting substance, prepare the hydroxide, study its properties, namely, its reaction with oxygen, air, acids, and alkalies. 

Add bromine water to a small amount of the precipitate. What is formed What properties does manganese (I I) hydroxide have Write the equations of the reactions. 

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

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

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. 

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. 

Uranium(IV) chloride prepared by this procedure contains traces of free carbon in the range 25-300 ppm. This impurity, however, has no effect for subsequent use in the synthesis of organouranium(IV) and other compounds. 

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... 

Sodium hexametaphoaphate [(NaPO )g] also precipitates uranlim (rv) from acid solutions.Adherence to fairly stringent conditions allows for complete precipitation. A 3HH510jj solution of uranium (iV) is heated to 60-70 C. If more than 2 mg. of uranium are to be precipitated, a freshly prepared 2 hexametaphoaphate solution is added until its concentration in the precipitating medium is 0.30-0.35 per cent. To precipitate smaller amounts of uranl im, a 0.5 per cent solution of thorium chloride Is added as carrier and the hexametaphoaphate added until it is in excess 25 per cent with respect to the thorium, l.e., molar ratio of ThiPO ... 

Uranium exhibits oxidation states from +3 to +6, although U(IV) and U(VI) are the more common. The key starting point for the preparation of many uranium compounds is UO2 and scheme 24.37 shows the syntheses of fluorides and chlorides. The fluoride UF5 is made by controlled reduction of UFg but readily disproportionates to UF4 and UFg. 

IV. Many variations of the reaction of uranium chlorides with metallic Na in sealed iron vessels have been described. The products range in purity from 99 to 100% U. The preparative method described below is based on the earlier procedures and attempts to overcome some of their shortcomings however, it affords a uranium whose x-ray diffraction pattern still clearly shows UO 3 lines. For this reason one must question the assertions of earlier authors who claimed that this procedure gives a completely pure product. 

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