Coordinating properties of actinide (V) dioxocations

The study of composition and IR spectra of some AnO+2 (An=Np, Pu, Am) compounds and their complexing in water solutions showed that, AnO+2 ions are linear, symmetric groups in their anhydrous complexes. AnO+2 ions do not have a fixed coordination number, it may be 4, 5 or 6 in different compounds. In similar types of bond, the An-O and An-ligand bonds are weaker in AnO+2 compounds than in AnO2+2 compounds. This fact determines the specificity of AnO+2 complexing in solutions. In the series Np, Pu, Am the bond strength of An-O in AnO+2 complexes decreases slowly and monotonically. In contrast to AnO2+2, O-atoms of AnO+2 are characterised by chemical activity and may react as proton-acceptors. (Auth.)