Uranyl ion complexation by citric and tricarballylic acids: hydrothermal synthesis and structure of two- and three-dimensional uranium-organic frameworks.

The first crystal structure of uranyl citrate is reported, as well as that of uranyl sodium tricarballylate; both compounds are polymeric, with all acid groups coordinated, but they differ strongly in their coordination modes; the resulting assembly architecture is either three-dimensional with [(UO2)2(Hcit)2]2- metallacycle subunits with citrate or two-dimensional with tricarballylate.