Curium chlorides

A number of compounds of curium have been produced, including two forms of curium oxide (Cm203 and Cm02), two forms of curium fluoride (CmF3 and CmF4), curium chloride (CmCl3), curium bromide (CmBr3), and curium hydroxide (Cm(OH)3). 

Calcium urateff,— Tha neutral salt, C,H,N,0,Ca, is obtained by dropping a solution of neutral potassium urate into a boiling solution of curium chloride until the precipitate is no longer redissolved, and then boiling for an hour. A granular powder, soluble in 1600 paris of cold H,0 and in 1440 parts of boUing H,0. 

In general, the absorption bands of the actinide ions are some ten times more intense than those of the lanthanide ions. Fluorescence, for example, is observed in the trichlorides of uranium, neptunium, americium, and curium, diluted with lanthanum chloride (15). 

Americium and other actinide elements may be separated from lanthanides by solvent extraction. Lithium chloride solution and an eight to nine carbon tertiary amine are used in the process. Americium is then separated from curium by the above methods. 

When curium is heated with fluorine at 400°C, the product is CmF4, a tetravalent curium compound. However, heating with other halogens yields trivalent halides, CmXa. Similarly, when heated with hydrogen chloride gas at 500°C, the product is curium(lll) chloride, CmCls. 

Cuprous chlorides, ionization, 9 297 Curie temperature dependence, of paramagnetic species in NMR, 32 15 Curium... 

In americium and curium extraction from chloride solutions by HDEHP in n-heptane, dependence of the extraction coefficient on hydrogen ion concentration and HDEHP concentration indicates an... 

Curium, berkelium, californium and einsteinium were separated from the americium samples irradiated by neutrons. For preliminary separation the anion exchange in hydrochloric acid and lithium chloride solutions was used as well as the HDEHP extraction. Mutual separation of the transamericium elements was made by using DIAION CK08Y cation exchange resin. Nuclides prepared and separation methods adopted are summarized in Table 1 (1-15). 

Freeman and Smith (32) have prepared the anhydrous chlorides of a number of lanthanides and of thorium by dehydrating the hydrated chlorides with thionyl chloride. Although efforts to obtain anhydrous plutonium trichloride in this way were unsuccessful, it is believed that this may be a useful procedure for actinide elements such as actinium, americium, and curium that have a particularly stable (III) oxidation stage. In general, aqueous methods for preparing tetrachlorides are of little value but anhydrous trichlorides, particularly of the transuranium elements, can be obtained readily from the hydrated trichlorides by dehydration in an atmosphere of hydrogen chloride. 

Am(iii) is sorbed much more strongly onto anion-exchange resins from concentrated lithium chloride solutions than are the lanthanides [61], Americium distribution ratios increase with increased lithium chloride concentration (Fig. 8.1), whereas increased temperature enhances the separation of americium from rare earths. A lithium-chloride-based anion-exchange process for separating multigram amounts of americium and curium from lanthanide fission products and to isolate an Am-Cm fraction free of heavier actinides is routinely operated at the Oak Ridge facility [14]. 

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