Synthesis and crystal structure analysis of uranyl triple acetates

Single crystals of triple acetates NaR[UO2(CH3COO)3]3·6H2O (R=Mg, Co, Ni, Zn), well-known for their use as reagents for sodium determination, were grown from aqueous solutions and their structural and spectroscopic properties were studied. Crystal structures of the mentioned phases are based upon {Na[UO2(CH3COO)3]3}2– clusters and [R(H2O)6]2+ aqua-complexes. The cooling of a single crystal of NaMg[UO2(CH3COO)3]3·6H2O from 300 to 100 K leads to a phase transition from trigonal to monoclinic crystal system. Intermolecular interactions between the structural units and their mutual packing were studied and compared from the point of view of the stereoatomic model of crystal structures based on Voronoi-Dirichlet tessellation. Using this method we compared the crystal structures of the triple acetates with Na[UO2(CH3COO)3] and [R(H2O)6][UO2(CH3COO)3]2 and proposed reasons of triple acetates stability. Infrared and Raman spectra were collected and their bands were assigned