From Nd(III) and Pu(III) Oxalates to Oxides: Influence of Nitrilotris(methylenephosphonic acid) on Chemical Composition, Structure, and Morphology

Neodymium oxalate structure and morphology were modified by adding a phosphonate, NTMP, during the oxalic precipitation step. Spherical agglomerates of neodymium oxalate Nd₂(C₂O₄)₃(H₂O)₆·12H₂O composed of thin hexagonal rods were precipitated instead of decahydrated oxalate Nd₂(C₂O₄)₃(H₂O)₆·4H₂O with rod-like particles usually obtained in the absence of additive. Despite some differences in the complexation with NTMP and complexity from redox, the use of NTMP was successfully transposed to the plutonium system. Spherical agglomerates of plutonium­(III) oxalate were so obtained, leading to spherical agglomerates of PuO₂ after thermal treatment.