Octahedral Hexahalide Complexes of the Trivalent Actinides

The trivalent actinides, like the trivalent lanthanides, form only weak chloride complexes in aqueous solution, and although there is evidence of slight formation of anionic complexes in concentrated LiCl from anion exchange data, no anionic chloride complexes have previously been positively identified. Ryan and Jørgensen have recently prepared the trivalent lanthanide hexachloro and hexabromo complexes and studied their absorption spectra. This paper discusses preliminary results of the extension of this work to the trivalent actinides.