Knowledge Bank

The infrared spectra of aqueous solutions of U(VI), Np(VI), Pu(VI), Am(VI), Np(V), and Am(V) ions have been observed. Due to strong water absorption, it was necessary to use very short path lengths (5-10 microns) and fairly concentrated solutions ($>0.5$ formal in U, Np, etc.). All of the (VI) ions exhibit fairly sharp infrared absorption bands in the region $935-965cm-1$. The (V) ions exhibit considerably broader bands in the region $815-830cm-1$. From this and other evidence, the conclusion is that they are all doubly oxygenated. The technique in obtaining these spectra is described. From the observed results, X-O bond force constants are calculated. These force constants are used to calculate approximate bond distances by using an extrapolation of Badger's rule. The structure of the ions is briefly discussed. The effect other ions have on the O-X-O frequency, $\nu 3$, is considered.