Comparisons of Plutonium, Thorium, and Cerium Tellurite Sulfates

The hydrothermal reaction of PuCl3 or CeCl3 with TeO2 in the presence of sulfuric acid under the comparable conditions results in the crystallization of Pu­(TeO3)­(SO4) or Ce2(Te2O5)­(SO4)2, respectively. Pu­(TeO3)­(SO4) and its isotypic compound Th­(TeO3)­(SO4) are characterized by a neutral layer structure with no interlamellar charge-balancing ions. However, Ce2(Te2O5)­(SO4)2 possesses a completely different dense three-dimensional framework. Bond valence calculation and UV–vis–NIR spectra indicate that the Ce compound is trivalent whereas the Pu and Th compounds are tetravalent leading to the formation of significantly different compounds. Pu­(TeO3)­(SO4), Th­(TeO3)­(SO4), and Ce2(Te2O5)­(SO4)2 represent the first plutonium/thorium/cerium tellurite sulfate compounds. Our study strongly suggests that the chemistries of Pu and Ce are not the same, and this is another example of the failure of Ce as a surrogate.