Organic complexes
Chemistry of Actinides. Complexes and Solids in Aqueous Medias

Actinides interact with organic compounds, particularly those with oxygenated complexing functions. As in the case of inorganic complexes, the formation of chemical bonds between the actinide or actinyl ion and carboxylate functions displaces molecules of water of hydration. This therefore induces several contributions to the free enthalpy of reaction Δ_rG⁰ = Δ_rH⁰ - TΔ_rS⁰; often, complexation with single ligands is favored by entropic gain due to dehydration of the actinide or actinyl ion, whereas it has an enthalpic cost. When ligands have a chelate effect, i.e. complex ions with different chemical functions, enthalpic and entropic contributions to the free enthalpy of reaction are trickier to define on a general level.

Simple carboxylic acids, such as acetate, propionate or isobutyrate, form moderately stable complexes with...