Crystal growth methods dedicated to low solubility actinide oxalates

• Use of diester as oxalate precursor for crystal growth of actinide oxalates.
• Use of actinide oxide as precursor for crystal growth of actinide oxalates.
• Crystal growth of Pu(III) and Am(III) oxalates.
• Crystal growth of mixed Pu(III)/Pu(IV) oxalates.

Two novel crystal growth syntheses dedicated to low solubility actinide-oxalate systems and adapted to glove box handling are described. These methods based on the use of precursors of either actinide metal or oxalic acid have been optimized on lanthanide systems (analogue of actinides(III)) and then assessed on real actinide systems. They allow the synthesis of several actinide oxalate single crystals, Am2(C2O4)3(H2O)3·xH2O, Th(C2O4)2·6H2O, M2+x[PuIV2−xPuIIIx(C2O4)5]·nH2O and M1−x[PuIII1−xPuIVx(C2O4)2·H2O]·nH2O. It is the first time that these well-known compounds are formed by crystal growth methods, thus enabling direct structural studies on transuranic element systems and acquisition of basic data beyond deductions from isomorphic (or not) lanthanide compounds. Characterizations by X-ray diffraction, UV–visible solid spectroscopy, demonstrate the potentialities of these two crystal growth methods to obtain oxalate compounds.

Two new single crystal growth methods dedicated to actinide oxalate compounds.Figure optionsDownload as PowerPoint slide