Chemical trends within the periodic table are frequently used as guides for predicting reactivity, structure, and electronic properties of the elements. While these trends have been rigorously investigated for the transition metals, the understanding of trends within the actinide series is elementary in comparison. Herein, we report the synthesis and characterization of five new U(IV) sulfate compounds and discuss their relationship to previously reported An(IV) sulfate species, an analysis that allows for the elucidation of solid state trends across the actinides. One such trend suggests the increase in Lewis acidity that occurs when traversing the actinides from thorium to plutonium promotes bidentate binding of the sulfate ligand as long as complexation can outcompete the resulting increase in steric pressure. This hypothesis correlates well with the experimental results previously reported for the solution phase speciation in An(IV) sulfate systems.