Abstract <p>Wheels clusters are interesting because of their unique structures and potential applications. As a group of well-known wheel clusters, octanuclear metal-sulfate wheels have been widely studied. However, investigations on tuning the packing modes of octanuclear metal-sulfate wheels are rarely reported. In this work, we synthesize an octanuclear iron-sulfate cluster (Fe₈-Wheel) by a solvothermal method. Three different packing modes of Fe₈-Wheels are successfully achieved by varying the sulfate to metal ratio in the reaction solution. With low sulfate content, compound FeWheel-1, consisting of zig-zag layers of Fe₈-Wheels, can be synthesized. When the sulfate ions are in large excess, we obtain FeWheel-2 and FeWheel-3, both containing cubic pseudo-cage units assembled by six Fe₈-Wheels. The hydrogen bonding between the uncoordinated sulfate ions, dimethylammonium counter ions, and Fe₈-Wheels dictate the packing modes. The discovery of these new packing modes provides insights on how to assemble wheel clusters into more complicated architectures by exploiting the guest species.</p>